HOW WILL WE IMPROVE NEXT TIME? - Since doing this video, we have updated our opinion on how best to install reflectix. The information that we conveyed in the video is correct, and the relfectix can be installed either way when it comes to radiance, but an aspect that we didn't consider as much as we should have was conductivity. By sticking the reflectix to the metal of the van directly, that connection forms a thermal bridge and increases the rate of heat transfer. So, we would stick the reflectix onto the back of our wall cladding to act as a radiant barrier. However, that would make it nearly impossible to make a seamless moisture barrier. For the moisture barrier, we would use a different material (not metallic) to stick directly onto the metal first (before the framing or reflectix) for it to cover all exposed metal, which would reduce the risk of condensation, and it would stop moisture from going in. It is our opinion that it is best to use different materials for the moisture barrier and the radiant barrier. Reflectix as an insulator (radiant barrier) is 100% worth it to install for its insulation properties, but we don't think it is the best material to use as a moisture barrier in a van. A moisture barrier is very important, especially since any exposed metal will condense water immediately. A few materials that we are thinking of trying are some neoprene sheets or a housing plastic membrane...we'll update you during the next van build. ~Happy building!
maybe have a look into fire retardant CORREX™ (lightweight twin-wall polypropylene sheets, available in various thicknesses) it might be useful for the stand-off battening instead of wood.
Any type of material that is lined with aluminium is the best vapor barrier there is compared to any plastic, as aluminium is essentially imperimable, whilst plastics are still slightly permiable. As for the conductivity, which you think is a problem if reflectix is stuck directly to the metal of the van - that's not really a problem, as the reflectix is not a better conductor of heat than the metal itself and so it doesn't really matter whether there is a small thickness of reflectix added between your framing and metal as the metal itself is a super-conductor and will thermal-bridge the wall from outside to inside (or vice versa), essentially. Lets put it this way - a 10mm thick metal wall is a better insulator than a 7mm thick metal wall, even though none of them are a good insulator. The framing in these instances will be the best thermal-bridge braker between the metal (or reflectix) and your wall panels. Sure, wood is not the best insulator and you might find a better material to brake the thermal-bridge, but 25mm of wood is way better than none. Havent seen this done and I'm not sure it would actually work, but, if structural properties are not essential for a build and the only thing someone is interested is a thermal-bridge braker between metal and plywood, I suppose strips of XPS or PolyIso could be used similarly to framing at all the "high" spots of metal where the plywood wall panels would directly contact it if they were laid purely on top of it. Then the plywood would be screwed to the metal with self-tapping screws through those insulation strips. They are load bearing enough to walk on them so, I suppose, if plywood with thickness of some 9mm or similar would be used this could workout great and provide the best posibile solution from the insulation perspective. As for the radiance and side of installation of the reflectix - it is not really true that there is no difference to which side it is installed to relative to the air gap as well as the source of heat. We know that hot air always travel towards cold air (i.e., the heat is traveling from hot to cold, not other way around). Reflectix works by trying to radiate the heat (hot, not cold) back towards its source. The air gap must always be between reflectix and the heat source for the reflectix to work at is maximum efficiency, because in that case the conductive heat transfer is limited as much as possible between a surface that is on the hotter side of the structure (in the case of van, for example, the outside metal or the inside plywood walls) and the reflectix, whilst forcing the heat to try and radiate over the air gap. The air gap then, esssentially, disperses the heat "uniformely", reflective material can reflect it back into the air gap to heat that air and thus contain that heat energy to the "hot side" of the panel. If the air gap is installed on the cold side of the panel, than, firstly, there is maximum contact between reflectix and the surface that is the "hotest" (the ones closer to the hear source), thus, the main heat transfer mechanism becomes conduction. Essentially, it up to us to design the structure to force radiant heat transfer instead of conductive heat transfer and than to use reflectix to prevent it as much as possible! So, to decide on which side of the reflectix you want to have the air gap you have to consider a few things. Firstly, lets assume that all of us throughout the year want a stable inside air temperature, of, say, 22 degrees celsius. Now, whenever the outside air temeperature is lower than this, the heat transfer will be from inside to outside (that is, the heat source will be on the inside). Whenever the temperature outside is higher than those 22 degrees, the heat transfer will be from outside to inside (thus the source will be on the outside). The bigger the differnece between the outside and the inside temperature, the more heat is transfered. Thus, for a typical van in, say, northern Europe, UK or similar places where usually outside temperature is lower than the inside temperature most of the heat transfer will be in the form of heat loss from the inside (not gain from the outside). Thus, what we want reflectix to do is radiate our produced inside heat back to us. That means that the air gap needs to be on the inside of the van as you have it in this video (or the other video of you van build). This also provides the best possible vapor barrier solution. Hope it helps!
The best way to implement a vapor barrier in a van is with a thin (7-10mm), self-adhesive closed-cell foam layer directly on the metal. Armaflex AF is the best material you can use. In the UK you can find Dodo brand closed cell-foam which is just as good but rather expensive. On top of it you can add as much insulation as you can fit, (preferably PET like the one you used) and last, a radiant heat reflector with as big of a gap as possible and as little contact with the outer walls as possible.
My head is spinning after weeks of pouring over videos and message boards regarding radiant heat barriers, specifically reflectix. Your explanation totally calmed my brain down! Thank you SO much for the straightforward explanations and physical examples!!
Glad we helped 🙂 We were in the same boat for ages during the research stage and, like you, we spent too much of our life debating this topic 😂... Glad the video is doing its job.
Thanks for the vid. I'm building my 3rd van and am actually going for another option. I'm insulating away all bare steel with Armaflex first. Then I fill up with polyester wool and then maybe reflectix at the back of the final wooding layer. No moisture barrier since warm air that travels through the walls/interiour will not be able to hit any cold steel (since the steel is already insulated away with Armaflex). Even as thin as 6mm Armaflex will prevent condensation.
That's nice, we wish we had insulated any exposed metal with some insulation like that as any metal condensates alot in the wheel arches which is the main exposed area. As long as the reflection has an air gap, it will work for insulation purposes too 😉
In our case, putting the reflectix directly to the metal and then the framing on top gives us more access. We can see where the framing is, add more framing if we need to without breaking the reflectix. We can also still use the van metal itself to bolt something onto if necessary. If we were to do the framing, and then cover it with the reflectix, we won’t have any reference points. Insulation wise, one way is not better than the other, they will both perform equally, but for practicality, we chose to put it on the metal. 👍
You are spot on with your explanation of radiant heat and vapour barriers. I've seen so many (well known) van builders totally misunderstand what reflectix is meant to be used for. Many even saying it's insulation, which of course is wrong! I fear though that your wise words will be lost on the diehards who can't or won't listen to reason. I've stopped banging on about it, let them waste their money installing reflectix without an air gap. You, however, will benefit because you've done your research. Well done.
Even if only 1 person takes on board our explanation, then it will be worth it! It wasn't that easy to find out the information yet alone understand it to help others, so thanks for the encouragement 😊
Thanks guys. I love your videos because you are so good at explaining the little science bits. I'm an artist so not much of a head for science but you help me to get it. Much appreciated ❤️
Great video, technical yes but absolutely necessary. For live in builds , understanding the effect of moisture and the dew point can be make or break a van build.
Totally agree, and it's so tricky to understand and get right. The hard part is that if you change 1 factor, you can make condensation and mould worse, so it's important to get right. We're still learning ourselves. 😉😊
First, thank you so much for the information. I was pretty gungho to use this in my van build.. but on researching have come across some questions that I need to have resolved first I think. All my "show stoppers" are for heat, and not cold. Because the heat in our vans is not radiant heat. It helps I believe in winter as a barrier but it's main use is for heat and "reflective heat". So this is really summer heat and sun I have seen and heard enough to wonder if I should. Q: The roofs of our vans are a vapor barrier as well as an air barrier. All products like Reflectix need an air gap to work. The R value for the product is minimal and it really uses the air gap to get it's R rating. When we put up a continuous covering and tape it with an air gap so it works. Where is that super heated air going. One person from one of the products like this in response to a question, said it becomes super heated, and of course, it is HOT on my roof now and radiates heat into my van, and he said it will be trapped in-between the layers and nowhere to go. It works on housing, roof attics etc, because the heated air has an escape and doesn't just get hotter and hotter and is "trapped" by the barrier of our roof, and the one we create with Reflectix. A: What happens then? I don't know, and hope someone has a practical answer to alleviate my concerns. BTW, I am leaning on putting it up, and have Thinsulate to use as my primary insulation, and "think" that might reduce "some" of the radiant heat from my roof, but I sure don't want to have a big problem down the road when I get all the roof, cabinets etc etc installed and have to take it down "because.. oh no". Thanks again and please don't take this in a negative way. I enjoyed both of you and your thoughts. But see some issues in what I have been able to research. And the manufacturers comments I have seen don't make me warm and fuzzy about this application either. All the best,
No insult taken, vans are really not designed to be insulated it seems and the research is an endless pit, so we all have to do what we can, thanks so much for your analysis and research, it's great to hear all research people have done so we can better our building techniques in the future ☺️👍
@@FreedomStrider Thank you for your kind and understanding response. All the best in your van build and adventures in your van too! I guess we will see how it works, lol. I will update if I find I made a "big" mistake with Thinsulate and Reflectix mix..I will be prayin' for your travels!
@@jaybennett7316 Wondering how it went? Did you end up putting it in your van? If so what are the results? I am thinking about doing the same, but now not sure either since the heat has nowhere to go.
Glad it was helpful! We know only too well how long research can take, we were just the same, it took us ages to commit to a step before taking it. You are doing great 👍😀
I have a LWB Sprinter 2012 75Km which was used as a mobile workshop. It was originally kitted out with work benches shelving and draws. People worked inside the van. There was only rust behind the wheel arch and van skin. I hooked out the sealant poored "Cure rust into the paper thin gap until it ran through onto the road." Then reseal behind the wheel Arch. There was no insulation in the van. What the previous owners have done is sprayed wax oil in all all the cavities below the inside floor level around the inside of the van cavities/ pocked. I presume on the principle that air will condense on the inside skin of the van run down the inside skin of the van. Gather into these pockets coated with wax oil then out on to the road via the drain holes manufacture into the van. All the holes which are used to attach the outside plastic trim leak. I can see where the water has run into the cavities/pockets sprayed with wax oil then out onto the road via the drainage holes. I am going to insulate the van but I have no idea if I will install a vapour barrier.
All we can say about the vapour barrier is that it definitely made a difference, we could feel the heat radiating inwards on the cold winter days when we had an electric heater running, more so than the insulation alone. But there are potential drawbacks, you just have to be careful not to leave any exposed metal, because that will condensate and eventually cause rust behind your walls. 👍
Hello, I am a big fan of Reflectic and you gave one of the best explanations i have seen on van builds and just using Reflectix in general. I placed it in my attic in my house in the city 20 years ago. It went from me unable to even be be in there for 10 mins on sunny days to being able to move my bedroom up there. The only thing i wonder about is the conductive heat from the frame of the van transferring to the aluminum foil on the Reflectix and turning it into a big radiant heat sink for the skin of the van like the heat sinks on computers. i know the wood framing will work as a non metal conductive break once that is on but it would be interesting to hear if you can tell if you can feel the conductive heat through the whole of the Reflectix. +
Thank you 🙂 We only installed the reflectix in the autumn, and don't have proper heating in the van (yet) though running out AC electric heating inside during the winter, the reflectix has really made a big difference!! We can get the inside from 0-20C within 30-45mins and the metal on the outside stays cold. The only places where conductive heat seems to be a problem is where the reflectix is touching the band outside metal directly (like around the wheel arches), if you touch the reflectix in that area it is colder than the other sections, but still not freezing. In a van I think it's difficult to get a perfect insulation barrier but you do the best you can given the circumstances 😎👍
We found this video very helpful and easy to understand and actually followed the same process to do our insulation and vapour barrier. However, upon making some changes to our bump outs, we needed to dig down into our vapour barrier. Unfortunately, we did find that there has been condensation forming on the internal metal which has travelled through our vapour barrier and recycled bottle insulation. We're not quite sure what to do moving forwards. It's understandable that we were never going to get a perfect vapour barrier, but it's interesting to wonder that this surely must happen to almost every van build only the condensation on the metal just isn't visible unless you do strip your van back out. Any thoughts on this yourself?
Truthfully, I would not be surprised if that is indeed happening in every single van, with or without a vapour barrier. Primarily because fluffy insulation and chunks of PIR board cannot fully cover every single metal surface in the walls, it's just the way the settle in the cavities, there will be pockets. Any exposed metal (exposed metal that isn't touched by fabric, reflectix or any other insulation) WILL produce condensation when there is a temperature difference. The only way that we can think to fully prevent that is spray foam insulation EVERYWHERE (in every crack and every cavity). That is what we would do if we would do the van again, because you can put the reflectix on to act as the radiant barrier it is, without trapping moisture as a vapour barrier. Realistically, what you want is the radiant barrier, not a vapour barrier when working with the van (if you have exposed metal). On an already converted van, the best thing to ensure is that there is enough ventilation going through the walls to remove that moisture as the seasons change. You'll get that moisture with or without reflectix, the only way to stop it is to cover every metal surface or ventilate the walls extremely well (though that would make the insulation less efficient). It's a viscous circle and is really tricky to get the balance right, hopefully this helps you 🙂
@FreedomStrider well-said. I agree with you. I'm doing my metal garage door for radiant barrier purposes and have been working on making a proper air gap between the door and the Reflectix.
By installing the reflectix directly on the Van Wall where it touches metal you will be conducting heat into the van and then by leaving an air gap between the reflectix and your wall paneling you will be maintaining heat within the van. I would have installed the reflectix on top of the cladding behind the paneling to create an air gap between the metal wall of the van and the paneling. That would have prevented hot air from entering into the living space. You did a good job of explaining the concepts of conductive and radiant heat but then it doesn't seem like you followed those concepts in your actual build.
Great video but what i can't understand is ordinary vehicles dont have moisure barriers or vapour barriers. When it's freezing outside and were driving with the heating on, the roof should be damp and mouldy and every car should rust from the inside out. But they don't...what am i missing here..?
It's more for when the vehicle is off and not running a/c or heat. When you accidentally leave hot food in the car, or sleep in the car, in winter, moisture gets all over the inside of the windows and car. Multiply that by all the hours living in a van, I suppose.
Exactly this, normally cars will cool down and reach the same temperature as the outside, in a van the constant temperature difference causes condensation. In older cars there can be condensation rust caused by the years of this cycle too
Reading all the comments it seems to me that you should pack the walls and ceiling lightly with fluffy insulation and just add plenty of vents around the van. I reckon an extractor in the roof is a must. I'm going to have to find one that won't leak though!
Good ventilation is key, though if you mean, that vents will null the function of a vapour barrier then I doubt you can put enough vents and maintain the efficient circulation through the walls to stop the condensation forming. We covered our whole van in insulation and then the reflection and the reflection definitely made a difference with retaining the radiant heat.
Yes, in one you have van metal, reflectix, 18mm framing, inner wall And the other you have van metal, 18mm framing, reflectix, inner wall You still have an air gap in both cases, the location of that air gap is different. ☺️
What do you think about people who put foam boards between the framing ribs and then put the walls over that? Especially with reflectix under there as well. I want to layer more than one type of insulation so I can be in wider climate differences
It seems like you guys made a convincing argument against there being any point to even attempt a vapor barrier, and then went to great effort to create one without any explanation of why. As yourself and others have pointed out in the comments section, you will very likely get condensation on any exposed metal even with the vapor barrier. Nothing short of covering every square mm of metal with spray foam will prevent this. Only now, that moisture is going to have a much harder time evaporating off and may begin to pool. I understand that a wall with too much ventilation with loose some R value. However, it seems to me that a small amount of passive ventilation would be allot better than almost none. I'm in the beginning stages of my own build. I started by covering as much metal surface as possible with two layer sound deadening/ closed cell foam insulation. I then put 3M insulate on top of that. My main concern now is heat transfer through the uninsulated structural supports. I think I will add a layer of Reflectix on top of my wall framing with the air gap behind to address that issue. However, I will not seal the edges or holes for receptacles and lights because I want a radiant barrier, not a moisture trap. I'm also considering the feasibility of installing a vacuum hose in the walls, with the idea being to remove the inevitable moisture. You could have intake vents that normally remain closed and a port to hook a vacuum to each wall section for active ventilation. You would simply perform periodic ventilation of the wall with a small portable vacuum. You would not loose any R value, and have the ability to remove moisture.
We installed the Reflectix mostly for the radiant properties, it really made a difference insulation and temperature wise after we put in on, compared with just the insulation in place. If you don't put Reflectix with the hope that there will be enough circulation in the walls to dry up the moisture that forms from the temp difference, then I don't think there is enough circulation naturally to do that. Doing a mechanical vent system as you said may be able to balance it at the rate at which condensation forms (if done correctly) However if you think about window condensation and any other exposed metal condensation, those are open the room temperature air and if the outside is particularly cold, condensation will form insanely quickly and even putting the fan on doesn't really remove all of it. So taking all this into account, despite the moiusture trapping issue with Reflectix, we'd still advocate installing it for the radiant insulation properties, and to reduce some of the moisture. However if we were to do it again, we would eliminate the thermal bridges where the Reflectix touches the metal of the van, since this conducts heat and causes condensation on the inside. It reduces the effectiveness in those areas. And also, we would do an inside a mechanical ventilation system within the walls. That would be an interesting solution. Greg Virgie is very knowledgeable on this, his Reflectix experiment video very well demonstrates how the moisture forms instally Hope this gives you a lot to think out :)
Not quite, the reflectix needs an air gap next to one of its sides to be effective. Although insulation can be airy, it's not as effecient as an air gap. You can do: outside metal - insulation - wall frame - reflectix - inner walls Hope this helps 👌👍
Hello! Sorry for my English but i have question about vapor barrier. I found two ways of van insulation. Layers: 1. metal/insulation/wood framing/vapor barrier 2. metal/insulation/vapor barrier/wood framing (like on your video) What are the differences between these two methods? And why did you choose second one?
As long as you have an air gap between the wood framing and the vapour barrier in Option 1, then there is no difference between the two. We went with Option 2 as it was easier to see where our wood framing was (to attach things to it) and also the wood framing being on top straps down the vapour barrier, so there is less sagging. 😀👍
@@FreedomStrider thank you! So air gap is necessary between wood framing and vapor barrier(in option 1)? Because I've seen some people don't make this air gap(metal/insulation/wood framing/vapor barier/no air gap/finish wood boards). What are the consequences?
@@kir3230 The product itself has very little R value from what I have read and relies on an "air" gap to get it's R value. A big question that is stopping me at the moment is, where does all that heated air go between our roof and the barrier we create by putting Reflectix and using an air gap as we should? I read one say it becomes super heated because it just reflects back to the inside of the wall of the roof, and is trapped. It works on applications like roofs, attics etc, that have an escape for the heated air from the sun... Sun is my problem.. I use my van for surfing mainly and travel second.. But usually at sunny places. The coast is cooler, but not always, and definitely not driving down middle of California in desert to get there.
Great video! One question, would this order work: Van metal > Furring strips on van metal (1.5 inch gap created) > Reflectix on top of furring strips > 1/2 inch polyiso foam on top of reflectix > then panelling on top of polyiso foam? Thank you!
Theoretically, as long as you have an air gap of about 20mm next to your reflectix, then the reflectix would retain its radiant barrier properties. As for putting the insulation after you put the reflectix, theoretically, there's no problem with the system working, but most people put insulation first to fill the cavities in the van, and to preserve more width of the living space. So I'm just wondering how come you've decided to put it the reverse way around?
@@FreedomStrider there’s no real deep cavities in the van I’m converting (super small). It’s the only real way to get the significant gap for the reflectix and I’m concerned the reflectix on it’s own clearly won’t be enough as insulation. Only other option would be to ditch the reflectix altogether and just use the polyiso. With the foil side out is there any need for a Radiant barrier with the polyiso if I did get rid of the reflectix?
And one thing of note, I live in a warm non-humid climate. The thought with reflectix and radiant barrier was to reduce heat transfer and keep the van cooler.
By using foil tape and the foil on the Poli insulation, you wouldn't need reflectix since the foil tape does the same thing, but again the air gap is key 👍
Well the foil we used is shiny on both sides but if only one is shiny for, it should face the gap. So, in your case, once the foil is on, you should see the shiny foil. :)
The problem with vapor barriers (VB) has always been structural. It a house (or a van) if the building is 100% vapor barriered and you slam at door, an unsupported VB will flex. This constant flexing will eventually fatigue an unsupported VB (plastic or tin foil). Plus these materials are compromised when you attach the interior cladding over top (screws). An easy VB that is structurally supported is PAINT! Two coats of oil or latex paint applied to your finished surface, produces a great VB that is structurally sound. Plus if it is damaged, it is easy to repair with a touch up of paint.
What about running strips of plastic strapping (the sort often uses to attach loads to pallets and found in bins/skips) hot glued to metal framing to hold bulky insulation from intruding into the air space? I’m going to do it in my Toyota Hiace.
That could work, soft insulation works best when not compressed although it does need to be controlled on a way, we were thinking string and some people use heavy wood beams but the straps would work well for the soft stuff 👍
Any suggestions for permanently covering windows (that will be behind walls)? I was thinking of going with Reflectix on outside followed by Polyiso. Or should it be switched Polyiso then Reflectix to get the 1” gap? Want options for keeping it stealth when I go into cities…. Wondering if I sprayed outside layer (facing window) with like Flex seal or Plasti Dip? Thanks
Windows do let in the heat and the cold more than just the bare metalwork, especially the heat. Spraying the outside might work quite well, to block the light coming through if you didn't want the window at all. Keeping an airgap for the reflectix would still be best to give better insulation qualities. 👍
Yes, technically that is also reflectix, and so it the aluminium tape we used. As long as the reflective surface isn't broken and has an air gap, it will work the same. Reflectix has some bubble wrap between its 2 foil layers which gives a bit of extra insulation (not much) In theory, with the pir board and foil tape you could do a moisture barrier. The only thing we found was sticking foul tape directly over the metal parts still created condensation but using the reflectix over the metal caused no condensation 😎
Good vid. Reflectix has a poor R value and is a terrible radiant barrier. In fact it conducts heat. It's a very good vapour barrier though. I'm mulling it over right now for my build, and may go for something different.
Yes reflectix does have a poor R value but it only conducts heat if it makes direct contact with the heated surface. With an air gap, its radiant properties do make a difference, at least in our experience. As soon as we put reflectix in, the temperature control became alot more manageable 👍 I don't know a comparison of other materials that can be used for a radiant barrier so I don't know how good of a radiant barrier it is. I can only say that it does work 👌 As for the vapour barrier, I would really rather not have a vapour barrier, and had it not been for the radiant part of the reflectix I don't think we would have put the reflectix in. This is purely because if moisture does get trapped between the reflectix and the van metal then it will be very difficult for that moisture to escape. What different options were you thinking of using?
@@FreedomStrider Having or not having a VP lol. Greg Virgoe's experiment is rather compelling on YT - apparently he made it specifically because of other TH-camrs saying the opposite. He is a retired aircon engineer so his opinion must carry weight I guess. My wife and I will live in our van 9 months of the the year and that has to be a factor too. As a non expert I'm obviously undecided. However, my van does not have metal sides but as a Luton low loader has hardwood coated in protective plastic. It does have a channel at the bottom with holes so vapour does indeed have an escape route.
Thanks for the clear expectation. Since you chose using reflectix you are not really worried about trapped moisture even though that might happen? Do you have any ways to mitigate it if it happens or just hoping it won’t happen/be much?
Well, there is not much to do about the trapped moisture. The only thing is to install the moisture barrier in a dry environment. If you are doing it outside then a cold day is usually dryer and avoid rainy days. Note: check out pinned comment on how we would improve our installation 😊
Glad you found it helpful! We used Trimfix (amzn.to/32kMcIi) and it's stuck really well - we've also used this to stick fabric to the van for our headliner as well and it's good stuff ☺️
Here's an off the wall (no pun intended) question. Can the radiant barrier be on the outside (like Batman's underpants), e. g. via some sort of paint? I've read, for example, that car windscreens have a coating which acts to reflect a lot of radiant heat. Putting it on the outside would be easier to do - just one coat and no fiddly patches to deal with - and easier to patch if scraped or scratched. I realise that you would still have the vapour seal to achieve.
I think there are reflective paint, I think it's called Chrome paint, but I'm not sure how effective it would be, though it will certainly reduce the absorbsion rate. However, since it's so reflective I think around the world it's actually illegal for use on vehicles because it's reflectivity can cause accidents (by blinding people) We've heard some people considering the use of reflective paint on the roof for the same our, that was it's only helicopters and pigeons that will suffer the shine - the only issue with the paint (other than the possible illegality) is that you'd need to keep it clean all the time as dirt reduces it's efficiency
@@FreedomStrider Another question: I have seen on another excellent van build channel (HughTube) the use of automotive carpet, which seems to offer a vapour seal plus (possibly) sound (vibration) insulation and - I assume - SOME heat insulation. I am wondering whether this is a candidate for ticking all the boxes in one go, and avoiding the need for air gap, albeit not as effectively as having the various separate layers. You could still add an interior wall or at least battens to attach cabinets and so on to.
The only automotive carpet we can think of is the 4-way stretch carpet that most cars are lined with - it's what we used on our headliner. These carpets are not an all in one solution. I would say, they do help to dampen the vibrations and they do add a little insulation (though not enough to keep you warm in winter. As for the vapour seal, unless the carpet you are thinking of has been lined with reflectix or another non-breathable material on one side, the fabric itself is very much breathable, so it will not stop the vapour getting to the cold van metal. We are actually planning to use some stretch carpet to help us circulate the moisture in our walls. And for the radiancy protection, if there is no reflective surface (installed with an air gap) then that will not be covered with an automotive fabric either. The only way I can think of a carpet starting to be functional is if the carpet has been stretched on a non-breathable, reflective surface, and then that is somehow attached to the van's framing (leaving an air gap on the back). That will sort of, tick the radiancy protection, a bit of the moisture barrier (but not fully) and the fleecy fabric will be a bit insulating. However, there are a lot of red flags that would need resolving down that path. 🤔🙂
I’ve always thought that having a white van (as opposed to an expensive dark colour version) was the first thing to consider and reflective covers for the windscreen and side windows in the cab make a massive difference as soon as they are put up on even a U.K. sunny day😉 Ventilation via a roof vent is also key to keeping condensation at bay. Your explanation of conduction and radiant heat was great but don’t forget convection! Warm (damp) air rises...hence the roof vent idea!
I am not sure why you are saying that it will reflect heat both ways? For it to reflect heat both ways, you need to have an air gap on both sides (although the 'fluffy' type insulation would considered like 'air', right?). If you stick it to the metal of the van, it will only reflect the heat back to the van. If you stick it on the framing, it will reflect the heat back to the insulation of the outside. I 'feel' that the best way to use Reflectix, is to put it AWAY from the van wall. Because it is easier to warm a van during winter than to keep it cool during summer (provided you have good insulation). What would you say about that? Your feedback is welcome! How did you end up doing it in your van? And do you really feel that it's better to use Reflectix, instead of just adding more insulation, where the air gap is supposed to be?
As a general rule, whether you put the reflectix on the wall of the van or away from the wall - as long as you have the air gap on one of the sides then results will be the same. The video that explained it best to us is this one, the guy explains it visually very well: th-cam.com/video/E1IwS0_lpBc/w-d-xo.html The positon of the air gap, making no difference, the way we decided to put it on the van, was a decision based on other practical considerations. How easy is the reflactix to attach, How would we attach the cladding afterwards, What if we need to add framing... etc. As for adding extra soft insulation instead of reflectix (without doing the maths we can't be sure and we haven't experienced it to compare), but we are very happy with our insulation set up. As soon as we put the reflectix on, the climate in the van became much more balanced, even just us being in the van warmed the space up in winter (enough not to shake with cold). So, if we were to do it again, we would put reflectix on.
Well it is something that is quite unavoidable, if you were to use spray foam insulation and do it properly you might be able to eliminate moisture from your insulation cavities, but must vans have natural drain holes in the walls so the vans walls won't be air tight and moisture can still get in. The rigid PIR board should eliminate most moisture held in the walls (compared with rockwool which holds a lot more moisture), and with the drainholes unclogged at the bottom, moisture should be able to pass through. Due to the design of vans (being metal), they aren;t really designed to be insulated or have big temperature differences, so you have to do the best you can. Eventually, yes, moisture in the walls will cause rust but then again, regular vans condensate moisture on the inside of the metal walls on hot and cold days anyway, and with insulation taking up the majority of the space inside the wall cavity, it should help somewhat :)
I'm not sure, Havelock wool is New Zealand sheep wool, right? We haven't used it to compare. Things to consider, however, is the weight, smell and if the natural material is an irritant. Otherwise, I'm sure it will keep you warm.
Reflection means it reflects light for instance in a window it will reflect the sun away,if it's inside a van it might as well be plain old bubble wrap.
In the use case in the video, the Reflectix reflects infrared heat as well as light. The fact that you see it reflecting the light when exposed, doesn't mean that (when covered) it will lose its ability to bounce the infrared radiation. Infrared waves are not visible to the human eye, they are experienced as heat. That's why you need the air gap, when installing Reflectix as part of an insulation system, to allow the infrared radiation room travel through the air. Otherwise it will just conduct in and out.
Very informative video, so helpful. I'm at this stage now and struggling to decide. When you were describing it not being possible to create a complete air seal I thought you weren't going to install a vapour barrier but then you went ahead and attempted a vapour/radiant barrier in one (not criticising here!). I'm swaying on the side of no vapour barrier, if I therefore mount the relextix a few cm's offset from my pir board/bottle wool insulation would this provide a radiant barrier but also provide an opportunity for the insulation beneath to breath underneath / condensation dry? Assuming I would get more condensation beneath insulation but also will provide more chance for drying out. What a nightmare. I'm just scared of effectively trapping condensation! Thanks ☺️
The reason we went ahead with the reflectix despite the moisture trapping issue is because we decided that the radient property benifits of reflectix outweigh the rather poor vaper barrier options. So we installed the reflectix and we did our best to cover as many moisture entries as we could, and we definately saw a noticable difference in the insulation quality after installing the reflectix. When doing this type of insulation, you will always have some moisture trapped behind the walls.However 1) Ensure that there is no exposed metal, because that is where condensation will form. 2) If you put the reflectix on with some care, the moisture will be very little, so it will rarely cause an issue; leaks from any holes you drill are far more likely to cause rust and need repair. Also, installing your insulation on a cold, dry day without heating the van, would trap the least amount of moisture behind the walls, pruley because colder air has less moisture (obviously if it is foggy or raining, slightly different story)...of course your figers will be frozen and you'll need about 10 layers on but hey..options😂 Another thought, depending on your budget and if you've already bought some of the stuff or not, one way to eliminate the moisture issue the most effectivly would be spray foam insulation, Because the foam coveres every nook and cranny, no moisture can be trapped behind. We looked it up, if we were to call someone to come and do it, it would have been £1000 (so over double the insulation we've done in our videos).
Far Out Rides has a great section all about this if you’re still planning your insulation. They went for thinsulate and then EZ-Cool (now Low-E Insulation) over bare metal like the frame. Low-E and Reflectix are similar but Low-E has the added benefit of containing some insulation alongside the reflective Vapor barrier.
Hey both, great video! I was wondering... If indeed I can't afford to lose width-wise space in the sleeping area of the van, but could elsewhere, would it be worth installing a radiation barrier in just part of the van? Like the roof, and perhaps parts of the walls? Thanks for sharing your thoughts!
So I assume you mean you aren't going to install insulation in the part where you'd be sleeping width-ways? You can do partial reflectix - but you have to be careful because if your reflectix is not airtight, that will let some moisture in behind the walls, but it will also trap it there, which can cause problems. If you choose to go with partial reflectix, if you just do it on the ceiling, that's probably the easiest to isolate as the cavities on the ceiling are not as connected as the walls. You can do it on the walls as well, but I would recommend thinking about how to seal the edges of your reflectix, or ways that you can ventilate the walls so that the moisture that does enter, can vent out. I hope this makes sense 🙂
Is ripping your insulation the best way to create an air gap? Wouldn't it be better to just seal it up as tight as possible and get wider studs(framing) to create the air gap?
Ah I see what you mean. We ripped that so it would fit in the cavities, the fluffy insulation isn't a substitute for the airgap, our airgap is created by putting the framing over the top of the reflectix (shown in one of our later videos)
Thanks for the great info guys!! How do we feel about adding reflectix to polyiso board? I was thinking of attaching reflectix directly to van walls, then half an inch of dead space, then another layer of reflectix adhered to one inch of polyiso, then plywood wall. How do you see the moisture situation going? I live in a hot area so I feel like most moisture would evaporate within 24 hours, specially with the half inch of complete air flow in the dead space. Thank you for any help!
So from what I understand, you are not filling the wall cavities of your van with any insulation? If that's the case then that is not a bad way to deal with the moisture on the van metal, as you'll be leaving all the natural vent holes of the open. Also, you are right that in a hot climate the sun would dryout most things quite quickly. However, leaving the cavities empty and then doing the PIT board on the outside, would reduce your living space... so twist and turns 🙃 In the dead space after your reflectix, is that where you are putting framing? I'm just thinking that if your cavities are empty then you don't really need another air gap. As far as I can visualize, your insulation system is fine, it will work, and it could potentially manage the moisture more effectively than stuffing the cavities.
Hello, thanks for the video, very informative! I'm building a catering van and want to keep the heat to a minimum so that the commercial drink fridges don't work so hard to keep things cold. What do you think about styrofoam as an insulator? The problem I see with the fluffy insulation you used is that it can hold water in it if water gets into the walls of the van.
Styrofoam is not as good an insulator as some other options. If you're going to go with rigid insulation board in the walls, I would go with PIR insulation, it much better than styrofoam, though do be aware that shaping any rigin board in the smaller cavities would be nearly impossible and require a lot of patience. Now budget dependant, the best insulation that you can go with is spray foam insulation, especially if moisture is a concern. This will definitely not trap moisture in the walls, and condensation would be only around the windows, not anywhere within the walls. 👍
No you are right, ideally it shouldn't touch the metal as that would create a thermal bridge. Ideally you can stick some foam or another insulating material to the metal or on top of the reflectix (once stuck). In our case we actually had ply framing on top of the thermal bridges so a good portion of the bridging resolved at the next stage. But any place that did not would potentially condensate so to improve our insulation system I would stick some foam similar.
Why didn’t you just use the Reflectix perforated foil? It seems to have the same or better radiant qualities as the “bubble wrap” and it is perforated so you don’t have the same moisture issues.
I'm so confused, I thought that if you tape it to the metal without a gap there wouldn't be a break. What about the rib you taped it to? Thank goodness there are professionals for people like me.
Depends on your needs. We obviously recommend the recycled plastic insulation and PIR board that we used (links in video description) - though if you have the budget for it, spray foam insulation is another good option because that would fill up all of the little air gaps and kinks, and because all the metal will be covered, you will need no vapour barrier.
The easiest way to fix moisture problems is use the original full headliner. I did with my Sprinter 12 years ago. Not any signs of moisture damage. The original headliner breathes is a good insulation and sound deadener
Yes the original headliner is the same as you have above your head up front. Some Sprinters have this fitted right through to the back doors, usually the bus with 12+ seats. I found a damaged van at the wreckers and removed all 4 sections. Good luck with your build
No, we didn't put any reflectix on the sliding door because there isn't enough room to provide the airgap necessary for the reflectix to be any good. For the reflectix to work we need at least a 12mm gap, and the sliding door passes quite close to the van's body as the door opens so there isn't that much clearance to have the air gap and then the cladding on top. (each van is different so you do need to check, but that's why, and it's not worth it for the moisture barrier). 😊👍
I did my insulation and vapour barrier the same way as you for the same reasons. Have you done your curved cab roof yet? As its a complicated shape i did mine with the space blanket insulation. The foil kind with 10 or more layers and can be shaped into all the curves.
Over the cab, with the headliner shelf - we put soft insulation and then reflectix and then stretch carpet - thought the reflectix is not there for radiancy, but mainly for structure. We couldn't figure a simple way of creating an air gap in such a curvy space with our shelf design, however, if we hadn't removed the headliner itself, we could have stuck reflectix on the back of it. That would have created an air gap between the metal and the headliner but it would have skipped the soft insulation. 😀
@@FreedomStrider cool that layering should work aswell. I find some common sense goes a long way with adapting your insulation as long as you stick to the important points.
@@FreedomStrider Do you think that the way that you did is insulating more than the way with sticking reflectix on the healiner(if i do it this way is it going to be better to also ad some more soft insulation or just leave only the reflectix to do its job)
The way the headliner insulation is done is the wrong way to use the reflectix (we did it before understanding it fully). The best practice method for insulation is the way described in the 'reflectix' video - with an air gap. The no air gap in the headliner video, that negates the radiant function of the reflectix, but the soft fluffy insulation will still work as it should. If we were to do the headliner again, we'll either, skip the reflectix or work on an air gap. 🙂👍
@@FreedomStrider Am i right that the more airgap there is the more it is actually insulating therefore you can leave a lot of air gap if you stick the reflectix to the headliner without using soft insulation. Will this create more insulation properties than if you fill it up with soft insulation?
No, it will stop the radiation heat transfer both ways. I could write an essay on this 😊, but I think this person demonstrates it well: th-cam.com/video/E1IwS0_lpBc/w-d-xo.html
Only if you try and put them under the barrier (deep within the walls). Most of our wiring is either above the reflectix or externally mounted in decorative conduit... Though we have run some conduit through the walls for a few if them. So if there are breaks in the barrier from wires and such, you just have to do your best sealing the perimeter before closing the wall up.
@@FreedomStrider Hi, these adhesives work differently than the usual suspects. They need to be applied on both materials then you need to wait until it's dry to the touch and only then press the two materials together. Unless you used a very special one I don't know about, which case I stand corrected. Awesome work anyway, thank you for sharing and taking the time filming and editing it. I just started mine, hope you are enjoying yours!
There shouldn't be an issue attaching it directly to the van metal since there is a layer of bubblewrap inside the reflectix between the 2 shiny surfaces, which means it doesn't quite conduct the heat. That being said, if you were to just use the foil aluminium tape, stick that directly to the metal, which then produces condensation. So the bubblewrap reflectix you can stick to the metal, but the foil tape, it's best to avoid it. 👍 As we said in the video, you can put your framing first, then your reflectix. But depending on how you're mounting stuff, that may make it harder to create a full vapour barrier.
You don't need an Air Gap with Reflectix.. You can test this just by putting it on the outside of any windshield. See how much heat or cold is reduced from one side to the other. When the Sun comes out. It's minor with 5mm thickness double sided foil....
Whether you put the reflectix on the inside or outside of the windshield you still have an airgap on one side. Radiant heat is only transferred through air or vacuum (otherwise it is conduction heat transfer), without the airgap the heat will get absorbed and conduct rather efficiently.
@@FreedomStrider It matters a lot. As Reflectix has a builtin air gap to start with..Between both sides of the foil.. And like I said. Go validate it. Just cover the windshield. Inside and out. You will see the differences. As both sides will be touching the surface of the glass... The one on the outside test vs the one inside. I will wait while you go test it. Then tell my your findings.
The gap between the reflectix is proof that it needs space between to create the R-Value. Installing it correctly with up to 1/4-1/2 inch gap away from the heat source will give optimal R-Value.
@@R.L.U. Did you not read my post? I said it has it's "Own" air gap. You don't need any additional Spacing. Just go Validate it with a thermal gun. It makes no difference..
@@WizzRacing Sorry but you are wrong about that. First of all, there are different types of reflectix, for instance small and big bubble foil, woven foil and metalized foil. second: you MUST have an air gap to avoid conductivity with other objects, third: there is actually a sweet spot when it comes to an air gap, which might also be different depending on the application it is used for. I won't spoil all the details for you but you should read this paper about it: frsb.upm.edu.my/upload/dokumen/20191004083717Paper_3.pdf Also I recommend watching these two video's specifically: - Proof that foil radiant barriers don't work without air gap: th-cam.com/video/aU4q6RKaOQQ/w-d-xo.htmlsi=bM1QYCp2kSjvhISY - Proof that an air gap is required: th-cam.com/video/TdPLmbkhH2o/w-d-xo.htmlsi=IHL7fEXcTXplskVI I must add to this, that for windows an air gap might not make much difference, because glass is not a good conductor of heat, reflectix applied directly to glass may not have as significant negative of an impact as it would on a material like metal (inside a van in this case). Another important note here is that when applying reflectix with an air gap on the outside of the van (metal | air gap | reflectix | insulation | wall), you must make sure that the heat can escape between the metal and reflectix. I haven't read much about this but I feel like the hot air might get trapped leading to a negative impact. This is basically the only reason I can think of not adding reflectix apart from the existing vapor barrier issue it might cause. If anyone has more information on that topic please let me know.
right so i wasted £50 on bubble wrap and silver tape and now i've locked moisture in so my van will rot and I lined my van in carpet today before watching this video so too late to remove it haha never mind i know for next time!
You've locked in as much moisture as we have, so your van will not rot, don't worry! All you've lost is the radiant barrier benefits (so the airgap). We all live and learn, we did the same as you on our headliner before we understood the science. 😊
Ah yes the worst part of building a van! It was the best day of my life when we were done with reflectix. Never again! Also guys have the door open when you use that spray fix, cancer is real! Look on the back of the can. Also did you say you are using 18mm ply for your walls?
Actually doing the reflectix, not actually too bad. Researching how to install it correctly and why...fair point 😂 I agree with about the spray glue, we did have the back doors open with that stuff. At present we are using 18mm ply for the framing, not the actual walls (the walls are going to be 3mm poplar ply) 😊
Poplar ply is made of a different type of wood, so poplar is a softwood, whilst the hardwood ply that you find in most store can be made from birch, beach or spruce (I can't remember which - it varies per region and country). However, they are usually hardwoods and as such are double the weight. (e.g. 3mm hardwood = 2.3kg per m2 vs 3mm poplar softwood = 1.2kg per m2). However, poplar is less structural (even when thicker) so if you are to build a bed or a chair, it is structurally recommended to go with hardwood, but weight-wise, poplar is best. So you have to compare and compromise, depending on needs. 🙂
HOW WILL WE IMPROVE NEXT TIME? - Since doing this video, we have updated our opinion on how best to install reflectix. The information that we conveyed in the video is correct, and the relfectix can be installed either way when it comes to radiance, but an aspect that we didn't consider as much as we should have was conductivity. By sticking the reflectix to the metal of the van directly, that connection forms a thermal bridge and increases the rate of heat transfer. So, we would stick the reflectix onto the back of our wall cladding to act as a radiant barrier. However, that would make it nearly impossible to make a seamless moisture barrier. For the moisture barrier, we would use a different material (not metallic) to stick directly onto the metal first (before the framing or reflectix) for it to cover all exposed metal, which would reduce the risk of condensation, and it would stop moisture from going in. It is our opinion that it is best to use different materials for the moisture barrier and the radiant barrier. Reflectix as an insulator (radiant barrier) is 100% worth it to install for its insulation properties, but we don't think it is the best material to use as a moisture barrier in a van. A moisture barrier is very important, especially since any exposed metal will condense water immediately. A few materials that we are thinking of trying are some neoprene sheets or a housing plastic membrane...we'll update you during the next van build.
~Happy building!
maybe have a look into fire retardant CORREX™ (lightweight twin-wall polypropylene sheets,
available in various thicknesses) it might be useful for the stand-off battening instead of wood.
Any type of material that is lined with aluminium is the best vapor barrier there is compared to any plastic, as aluminium is essentially imperimable, whilst plastics are still slightly permiable.
As for the conductivity, which you think is a problem if reflectix is stuck directly to the metal of the van - that's not really a problem, as the reflectix is not a better conductor of heat than the metal itself and so it doesn't really matter whether there is a small thickness of reflectix added between your framing and metal as the metal itself is a super-conductor and will thermal-bridge the wall from outside to inside (or vice versa), essentially. Lets put it this way - a 10mm thick metal wall is a better insulator than a 7mm thick metal wall, even though none of them are a good insulator. The framing in these instances will be the best thermal-bridge braker between the metal (or reflectix) and your wall panels. Sure, wood is not the best insulator and you might find a better material to brake the thermal-bridge, but 25mm of wood is way better than none. Havent seen this done and I'm not sure it would actually work, but, if structural properties are not essential for a build and the only thing someone is interested is a thermal-bridge braker between metal and plywood, I suppose strips of XPS or PolyIso could be used similarly to framing at all the "high" spots of metal where the plywood wall panels would directly contact it if they were laid purely on top of it. Then the plywood would be screwed to the metal with self-tapping screws through those insulation strips. They are load bearing enough to walk on them so, I suppose, if plywood with thickness of some 9mm or similar would be used this could workout great and provide the best posibile solution from the insulation perspective.
As for the radiance and side of installation of the reflectix - it is not really true that there is no difference to which side it is installed to relative to the air gap as well as the source of heat. We know that hot air always travel towards cold air (i.e., the heat is traveling from hot to cold, not other way around). Reflectix works by trying to radiate the heat (hot, not cold) back towards its source. The air gap must always be between reflectix and the heat source for the reflectix to work at is maximum efficiency, because in that case the conductive heat transfer is limited as much as possible between a surface that is on the hotter side of the structure (in the case of van, for example, the outside metal or the inside plywood walls) and the reflectix, whilst forcing the heat to try and radiate over the air gap. The air gap then, esssentially, disperses the heat "uniformely", reflective material can reflect it back into the air gap to heat that air and thus contain that heat energy to the "hot side" of the panel. If the air gap is installed on the cold side of the panel, than, firstly, there is maximum contact between reflectix and the surface that is the "hotest" (the ones closer to the hear source), thus, the main heat transfer mechanism becomes conduction.
Essentially, it up to us to design the structure to force radiant heat transfer instead of conductive heat transfer and than to use reflectix to prevent it as much as possible!
So, to decide on which side of the reflectix you want to have the air gap you have to consider a few things. Firstly, lets assume that all of us throughout the year want a stable inside air temperature, of, say, 22 degrees celsius. Now, whenever the outside air temeperature is lower than this, the heat transfer will be from inside to outside (that is, the heat source will be on the inside). Whenever the temperature outside is higher than those 22 degrees, the heat transfer will be from outside to inside (thus the source will be on the outside). The bigger the differnece between the outside and the inside temperature, the more heat is transfered. Thus, for a typical van in, say, northern Europe, UK or similar places where usually outside temperature is lower than the inside temperature most of the heat transfer will be in the form of heat loss from the inside (not gain from the outside). Thus, what we want reflectix to do is radiate our produced inside heat back to us. That means that the air gap needs to be on the inside of the van as you have it in this video (or the other video of you van build). This also provides the best possible vapor barrier solution.
Hope it helps!
The best way to implement a vapor barrier in a van is with a thin (7-10mm), self-adhesive closed-cell foam layer directly on the metal.
Armaflex AF is the best material you can use. In the UK you can find Dodo brand closed cell-foam which is just as good but rather expensive. On top of it you can add as much insulation as you can fit, (preferably PET like the one you used) and last, a radiant heat reflector with as big of a gap as possible and as little contact with the outer walls as possible.
My head is spinning after weeks of pouring over videos and message boards regarding radiant heat barriers, specifically reflectix. Your explanation totally calmed my brain down! Thank you SO much for the straightforward explanations and physical examples!!
Glad we helped 🙂
We were in the same boat for ages during the research stage and, like you, we spent too much of our life debating this topic 😂... Glad the video is doing its job.
3 years late for the party , but by golly do you both have next level narrating skills. This was unreal and your such a cute couple.
Thank you 😊... you should see the out takes 😅
Thanks for the vid. I'm building my 3rd van and am actually going for another option. I'm insulating away all bare steel with Armaflex first. Then I fill up with polyester wool and then maybe reflectix at the back of the final wooding layer. No moisture barrier since warm air that travels through the walls/interiour will not be able to hit any cold steel (since the steel is already insulated away with Armaflex). Even as thin as 6mm Armaflex will prevent condensation.
That's nice, we wish we had insulated any exposed metal with some insulation like that as any metal condensates alot in the wheel arches which is the main exposed area. As long as the reflection has an air gap, it will work for insulation purposes too 😉
This has been the most helpful video! You’ve made it so simple to understand! Thank you 🙏
Glad you found it helpful :)
Well explained. Didn’t understand why it was better to put it directly on the metal.
In our case, putting the reflectix directly to the metal and then the framing on top gives us more access. We can see where the framing is, add more framing if we need to without breaking the reflectix. We can also still use the van metal itself to bolt something onto if necessary. If we were to do the framing, and then cover it with the reflectix, we won’t have any reference points. Insulation wise, one way is not better than the other, they will both perform equally, but for practicality, we chose to put it on the metal. 👍
You are spot on with your explanation of radiant heat and vapour barriers. I've seen so many (well known) van builders totally misunderstand what reflectix is meant to be used for. Many even saying it's insulation, which of course is wrong! I fear though that your wise words will be lost on the diehards who can't or won't listen to reason. I've stopped banging on about it, let them waste their money installing reflectix without an air gap. You, however, will benefit because you've done your research. Well done.
Even if only 1 person takes on board our explanation, then it will be worth it! It wasn't that easy to find out the information yet alone understand it to help others, so thanks for the encouragement 😊
Thanks guys. I love your videos because you are so good at explaining the little science bits. I'm an artist so not much of a head for science but you help me to get it. Much appreciated ❤️
You're welcome, Polly too, is an artist, and all the science takes a while to get your head around 😊
Great video, technical yes but absolutely necessary. For live in builds , understanding the effect of moisture and the dew point can be make or break a van build.
Totally agree, and it's so tricky to understand and get right. The hard part is that if you change 1 factor, you can make condensation and mould worse, so it's important to get right. We're still learning ourselves. 😉😊
I don't usually bother commenting but this was a great video. Really helpful. Thanks
Thank you ☺️ glad we could help
First, thank you so much for the information. I was pretty gungho to use this in my van build.. but on researching have come across some questions that I need to have resolved first I think.
All my "show stoppers" are for heat, and not cold. Because the heat in our vans is not radiant heat. It helps I believe in winter as a barrier but it's main use is for heat and "reflective heat".
So this is really summer heat and sun I have seen and heard enough to wonder if I should.
Q: The roofs of our vans are a vapor barrier as well as an air barrier. All products like Reflectix need an air gap to work. The R value for the product is minimal and it really uses the air gap to get it's R rating.
When we put up a continuous covering and tape it with an air gap so it works. Where is that super heated air going. One person from one of the products like this in response to a question, said it becomes super heated, and of course, it is HOT on my roof now and radiates heat into my van, and he said it will be trapped in-between the layers and nowhere to go.
It works on housing, roof attics etc, because the heated air has an escape and doesn't just get hotter and hotter and is "trapped" by the barrier of our roof, and the one we create with Reflectix.
A: What happens then? I don't know, and hope someone has a practical answer to alleviate my concerns.
BTW, I am leaning on putting it up, and have Thinsulate to use as my primary insulation, and "think" that might reduce "some" of the radiant heat from my roof, but I sure don't want to have a big problem down the road when I get all the roof, cabinets etc etc installed and have to take it down "because.. oh no".
Thanks again and please don't take this in a negative way. I enjoyed both of you and your thoughts. But see some issues in what I have been able to research. And the manufacturers comments I have seen don't make me warm and fuzzy about this application either.
All the best,
No insult taken, vans are really not designed to be insulated it seems and the research is an endless pit, so we all have to do what we can, thanks so much for your analysis and research, it's great to hear all research people have done so we can better our building techniques in the future ☺️👍
@@FreedomStrider Thank you for your kind and understanding response. All the best in your van build and adventures in your van too! I guess we will see how it works, lol. I will update if I find I made a "big" mistake with Thinsulate and Reflectix mix..I will be prayin' for your travels!
@@jaybennett7316 Wondering how it went? Did you end up putting it in your van? If so what are the results? I am thinking about doing the same, but now not sure either since the heat has nowhere to go.
Thank you so much! I appreciate your information! I am just starting! I don’t want to put anything up until I am certain! Now after this I can start!
Glad it was helpful! We know only too well how long research can take, we were just the same, it took us ages to commit to a step before taking it. You are doing great 👍😀
I have a LWB Sprinter 2012 75Km which was used as a mobile workshop. It was originally kitted out with work benches shelving and draws. People worked inside the van. There was only rust behind the wheel arch and van skin. I hooked out the sealant poored "Cure rust into the paper thin gap until it ran through onto the road." Then reseal behind the wheel Arch. There was no insulation in the van. What the previous owners have done is sprayed wax oil in all all the cavities below the inside floor level around the inside of the van cavities/ pocked. I presume on the principle that air will condense on the inside skin of the van run down the inside skin of the van. Gather into these pockets coated with wax oil then out on to the road via the drain holes manufacture into the van. All the holes which are used to attach the outside plastic trim leak. I can see where the water has run into the cavities/pockets sprayed with wax oil then out onto the road via the drainage holes. I am going to insulate the van but I have no idea if I will install a vapour barrier.
All we can say about the vapour barrier is that it definitely made a difference, we could feel the heat radiating inwards on the cold winter days when we had an electric heater running, more so than the insulation alone. But there are potential drawbacks, you just have to be careful not to leave any exposed metal, because that will condensate and eventually cause rust behind your walls. 👍
Hello, I am a big fan of Reflectic and you gave one of the best explanations i have seen on van builds and just using Reflectix in general. I placed it in my attic in my house in the city 20 years ago. It went from me unable to even be be in there for 10 mins on sunny days to being able to move my bedroom up there. The only thing i wonder about is the conductive heat from the frame of the van transferring to the aluminum foil on the Reflectix and turning it into a big radiant heat sink for the skin of the van like the heat sinks on computers. i know the wood framing will work as a non metal conductive break once that is on but it would be interesting to hear if you can tell if you can feel the conductive heat through the whole of the Reflectix.
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Thank you 🙂 We only installed the reflectix in the autumn, and don't have proper heating in the van (yet) though running out AC electric heating inside during the winter, the reflectix has really made a big difference!! We can get the inside from 0-20C within 30-45mins and the metal on the outside stays cold.
The only places where conductive heat seems to be a problem is where the reflectix is touching the band outside metal directly (like around the wheel arches), if you touch the reflectix in that area it is colder than the other sections, but still not freezing.
In a van I think it's difficult to get a perfect insulation barrier but you do the best you can given the circumstances 😎👍
We found this video very helpful and easy to understand and actually followed the same process to do our insulation and vapour barrier. However, upon making some changes to our bump outs, we needed to dig down into our vapour barrier. Unfortunately, we did find that there has been condensation forming on the internal metal which has travelled through our vapour barrier and recycled bottle insulation. We're not quite sure what to do moving forwards. It's understandable that we were never going to get a perfect vapour barrier, but it's interesting to wonder that this surely must happen to almost every van build only the condensation on the metal just isn't visible unless you do strip your van back out. Any thoughts on this yourself?
Truthfully, I would not be surprised if that is indeed happening in every single van, with or without a vapour barrier. Primarily because fluffy insulation and chunks of PIR board cannot fully cover every single metal surface in the walls, it's just the way the settle in the cavities, there will be pockets.
Any exposed metal (exposed metal that isn't touched by fabric, reflectix or any other insulation) WILL produce condensation when there is a temperature difference. The only way that we can think to fully prevent that is spray foam insulation EVERYWHERE (in every crack and every cavity). That is what we would do if we would do the van again, because you can put the reflectix on to act as the radiant barrier it is, without trapping moisture as a vapour barrier. Realistically, what you want is the radiant barrier, not a vapour barrier when working with the van (if you have exposed metal).
On an already converted van, the best thing to ensure is that there is enough ventilation going through the walls to remove that moisture as the seasons change. You'll get that moisture with or without reflectix, the only way to stop it is to cover every metal surface or ventilate the walls extremely well (though that would make the insulation less efficient).
It's a viscous circle and is really tricky to get the balance right, hopefully this helps you 🙂
@@FreedomStrider Glad to know we might not be alone in the boat! Lol thanks for the response. Take care both!
@FreedomStrider well-said. I agree with you. I'm doing my metal garage door for radiant barrier purposes and have been working on making a proper air gap between the door and the Reflectix.
Thanks clearer for me now as all my sound deadening and insulation has come thanks for the video i did get the right stuff 😉
Glad to hear it 😊
By installing the reflectix directly on the Van Wall where it touches metal you will be conducting heat into the van and then by leaving an air gap between the reflectix and your wall paneling you will be maintaining heat within the van. I would have installed the reflectix on top of the cladding behind the paneling to create an air gap between the metal wall of the van and the paneling. That would have prevented hot air from entering into the living space. You did a good job of explaining the concepts of conductive and radiant heat but then it doesn't seem like you followed those concepts in your actual build.
Great video but what i can't understand is ordinary vehicles dont have moisure barriers or vapour barriers. When it's freezing outside and were driving with the heating on, the roof should be damp and mouldy and every car should rust from the inside out. But they don't...what am i missing here..?
It's more for when the vehicle is off and not running a/c or heat. When you accidentally leave hot food in the car, or sleep in the car, in winter, moisture gets all over the inside of the windows and car. Multiply that by all the hours living in a van, I suppose.
Exactly this, normally cars will cool down and reach the same temperature as the outside, in a van the constant temperature difference causes condensation. In older cars there can be condensation rust caused by the years of this cycle too
Cars do actually rust from the inside out......
Very good explanation about air gap. Thank you.
Glad it was helpful! 🙂 It took us ages to understand it ourselves.
Reading all the comments it seems to me that you should pack the walls and ceiling lightly with fluffy insulation and just add plenty of vents around the van. I reckon an extractor in the roof is a must. I'm going to have to find one that won't leak though!
Good ventilation is key, though if you mean, that vents will null the function of a vapour barrier then I doubt you can put enough vents and maintain the efficient circulation through the walls to stop the condensation forming. We covered our whole van in insulation and then the reflection and the reflection definitely made a difference with retaining the radiant heat.
I don't understand the difference between what was said at 7:57 and 7:00. The cladding?
Yes, in one you have van metal, reflectix, 18mm framing, inner wall
And the other you have van metal, 18mm framing, reflectix, inner wall
You still have an air gap in both cases, the location of that air gap is different. ☺️
What do you think about people who put foam boards between the framing ribs and then put the walls over that? Especially with reflectix under there as well. I want to layer more than one type of insulation so I can be in wider climate differences
It seems like you guys made a convincing argument against there being any point to even attempt a vapor barrier, and then went to great effort to create one without any explanation of why.
As yourself and others have pointed out in the comments section, you will very likely get condensation on any exposed metal even with the vapor barrier. Nothing short of covering every square mm of metal with spray foam will prevent this. Only now, that moisture is going to have a much harder time evaporating off and may begin to pool.
I understand that a wall with too much ventilation with loose some R value. However, it seems to me that a small amount of passive ventilation would be allot better than almost none.
I'm in the beginning stages of my own build. I started by covering as much metal surface as possible with two layer sound deadening/ closed cell foam insulation. I then put 3M insulate on top of that. My main concern now is heat transfer through the uninsulated structural supports.
I think I will add a layer of Reflectix on top of my wall framing with the air gap behind to address that issue. However, I will not seal the edges or holes for receptacles and lights because I want a radiant barrier, not a moisture trap.
I'm also considering the feasibility of installing a vacuum hose in the walls, with the idea being to remove the inevitable moisture. You could have intake vents that normally remain closed and a port to hook a vacuum to each wall section for active ventilation. You would simply perform periodic ventilation of the wall with a small portable vacuum. You would not loose any R value, and have the ability to remove moisture.
We installed the Reflectix mostly for the radiant properties, it really made a difference insulation and temperature wise after we put in on, compared with just the insulation in place.
If you don't put Reflectix with the hope that there will be enough circulation in the walls to dry up the moisture that forms from the temp difference, then I don't think there is enough circulation naturally to do that. Doing a mechanical vent system as you said may be able to balance it at the rate at which condensation forms (if done correctly)
However if you think about window condensation and any other exposed metal condensation, those are open the room temperature air and if the outside is particularly cold, condensation will form insanely quickly and even putting the fan on doesn't really remove all of it.
So taking all this into account, despite the moiusture trapping issue with Reflectix, we'd still advocate installing it for the radiant insulation properties, and to reduce some of the moisture. However if we were to do it again, we would eliminate the thermal bridges where the Reflectix touches the metal of the van, since this conducts heat and causes condensation on the inside. It reduces the effectiveness in those areas. And also, we would do an inside a mechanical ventilation system within the walls. That would be an interesting solution.
Greg Virgie is very knowledgeable on this, his Reflectix experiment video very well demonstrates how the moisture forms instally
Hope this gives you a lot to think out :)
Can you put the reflectix directly on the metal? So in this order: outside metal - reflectix - isolation - wall frame and inner walls.
Not quite, the reflectix needs an air gap next to one of its sides to be effective.
Although insulation can be airy, it's not as effecient as an air gap.
You can do: outside metal - insulation - wall frame - reflectix - inner walls
Hope this helps 👌👍
Hello! Sorry for my English but i have question about vapor barrier.
I found two ways of van insulation.
Layers:
1. metal/insulation/wood framing/vapor barrier
2. metal/insulation/vapor barrier/wood framing (like on your video)
What are the differences between these two methods? And why did you choose second one?
As long as you have an air gap between the wood framing and the vapour barrier in Option 1, then there is no difference between the two. We went with Option 2 as it was easier to see where our wood framing was (to attach things to it) and also the wood framing being on top straps down the vapour barrier, so there is less sagging. 😀👍
@@FreedomStrider thank you! So air gap is necessary between wood framing and vapor barrier(in option 1)? Because I've seen some people don't make this air gap(metal/insulation/wood framing/vapor barier/no air gap/finish wood boards). What are the consequences?
@@kir3230 The product itself has very little R value from what I have read and relies on an "air" gap to get it's R value. A big question that is stopping me at the moment is, where does all that heated air go between our roof and the barrier we create by putting Reflectix and using an air gap as we should? I read one say it becomes super heated because it just reflects back to the inside of the wall of the roof, and is trapped. It works on applications like roofs, attics etc, that have an escape for the heated air from the sun... Sun is my problem.. I use my van for surfing mainly and travel second.. But usually at sunny places. The coast is cooler, but not always, and definitely not driving down middle of California in desert to get there.
I stumbled upon your video! Very, very informative and very well done. I’ll watch your video again as soon as I’m ready to insulate my bus ;)
Glad we can could help, it was a tricky topic for us to get right, all the best with your bus! 👍😎
@@FreedomStrider Thank you :)
Great video! One question, would this order work:
Van metal > Furring strips on van metal (1.5 inch gap created) > Reflectix on top of furring strips > 1/2 inch polyiso foam on top of reflectix > then panelling on top of polyiso foam?
Thank you!
Theoretically, as long as you have an air gap of about 20mm next to your reflectix, then the reflectix would retain its radiant barrier properties. As for putting the insulation after you put the reflectix, theoretically, there's no problem with the system working, but most people put insulation first to fill the cavities in the van, and to preserve more width of the living space. So I'm just wondering how come you've decided to put it the reverse way around?
@@FreedomStrider there’s no real deep cavities in the van I’m converting (super small). It’s the only real way to get the significant gap for the reflectix and I’m concerned the reflectix on it’s own clearly won’t be enough as insulation.
Only other option would be to ditch the reflectix altogether and just use the polyiso. With the foil side out is there any need for a Radiant barrier with the polyiso if I did get rid of the reflectix?
And one thing of note, I live in a warm non-humid climate. The thought with reflectix and radiant barrier was to reduce heat transfer and keep the van cooler.
By using foil tape and the foil on the Poli insulation, you wouldn't need reflectix since the foil tape does the same thing, but again the air gap is key 👍
@@FreedomStrider That's what I thought as well. Sounds good and thank you for getting back in touch!
Which way round does the shiny foil side face please? Sticking to walls as you are and leaving space between it and ply :)
Well the foil we used is shiny on both sides but if only one is shiny for, it should face the gap. So, in your case, once the foil is on, you should see the shiny foil. :)
The problem with vapor barriers (VB) has always been structural. It a house (or a van) if the building is 100% vapor barriered and you slam at door, an unsupported VB will flex. This constant flexing will eventually fatigue an unsupported VB (plastic or tin foil). Plus these materials are compromised when you attach the interior cladding over top (screws).
An easy VB that is structurally supported is PAINT! Two coats of oil or latex paint applied to your finished surface, produces a great VB that is structurally sound. Plus if it is damaged, it is easy to repair with a touch up of paint.
Thnaks, we'll have that in mind 🙂
What about running strips of plastic strapping (the sort often uses to attach loads to pallets and found in bins/skips) hot glued to metal framing to hold bulky insulation from intruding into the air space? I’m going to do it in my Toyota Hiace.
That could work, soft insulation works best when not compressed although it does need to be controlled on a way, we were thinking string and some people use heavy wood beams but the straps would work well for the soft stuff 👍
HI thank you for those clear explanations! You are the best. It really helps us to continue building our van!
You're welcome, all the best with your build 😎
Any suggestions for permanently covering windows (that will be behind walls)? I was thinking of going with Reflectix on outside followed by Polyiso. Or should it be switched Polyiso then Reflectix to get the 1” gap?
Want options for keeping it stealth when I go into cities…. Wondering if I sprayed outside layer (facing window) with like Flex seal or Plasti Dip? Thanks
Windows do let in the heat and the cold more than just the bare metalwork, especially the heat. Spraying the outside might work quite well, to block the light coming through if you didn't want the window at all. Keeping an airgap for the reflectix would still be best to give better insulation qualities. 👍
Any similar thought process regarding the reflective surface of the rigid foam insulation you have?
Yes, technically that is also reflectix, and so it the aluminium tape we used. As long as the reflective surface isn't broken and has an air gap, it will work the same.
Reflectix has some bubble wrap between its 2 foil layers which gives a bit of extra insulation (not much)
In theory, with the pir board and foil tape you could do a moisture barrier. The only thing we found was sticking foul tape directly over the metal parts still created condensation but using the reflectix over the metal caused no condensation 😎
Good vid. Reflectix has a poor R value and is a terrible radiant barrier. In fact it conducts heat. It's a very good vapour barrier though. I'm mulling it over right now for my build, and may go for something different.
Yes reflectix does have a poor R value but it only conducts heat if it makes direct contact with the heated surface. With an air gap, its radiant properties do make a difference, at least in our experience. As soon as we put reflectix in, the temperature control became alot more manageable 👍
I don't know a comparison of other materials that can be used for a radiant barrier so I don't know how good of a radiant barrier it is. I can only say that it does work 👌
As for the vapour barrier, I would really rather not have a vapour barrier, and had it not been for the radiant part of the reflectix I don't think we would have put the reflectix in. This is purely because if moisture does get trapped between the reflectix and the van metal then it will be very difficult for that moisture to escape. What different options were you thinking of using?
@@FreedomStrider Having or not having a VP lol. Greg Virgoe's experiment is rather compelling on YT - apparently he made it specifically because of other TH-camrs saying the opposite. He is a retired aircon engineer so his opinion must carry weight I guess. My wife and I will live in our van 9 months of the the year and that has to be a factor too. As a non expert I'm obviously undecided. However, my van does not have metal sides but as a Luton low loader has hardwood coated in protective plastic. It does have a channel at the bottom with holes so vapour does indeed have an escape route.
Awesome video ,thanks for posting definitely answered some questions I was having.
Glad it was helpful! 😀
guys what about the roof, would you install it there also ? thanks for all your informative videos, they really help
We did yes, and used the framing beams on the ceiling to attach our ceiling too, maintaining the air gap 👍
An absolute excellent video. Subscribed!
Thanks 😊👍... Glad to have you here.
Thanks for the clear expectation. Since you chose using reflectix you are not really worried about trapped moisture even though that might happen? Do you have any ways to mitigate it if it happens or just hoping it won’t happen/be much?
Well, there is not much to do about the trapped moisture. The only thing is to install the moisture barrier in a dry environment. If you are doing it outside then a cold day is usually dryer and avoid rainy days.
Note: check out pinned comment on how we would improve our installation 😊
I got aluminum air filled bubble insulation. Is this the same as the 1st step?
Thank you so much for your thoughtful video on reflects. What adhesive spray did you use please?
Glad you found it helpful! We used Trimfix (amzn.to/32kMcIi) and it's stuck really well - we've also used this to stick fabric to the van for our headliner as well and it's good stuff ☺️
Here's an off the wall (no pun intended) question. Can the radiant barrier be on the outside (like Batman's underpants), e. g. via some sort of paint? I've read, for example, that car windscreens have a coating which acts to reflect a lot of radiant heat.
Putting it on the outside would be easier to do - just one coat and no fiddly patches to deal with - and easier to patch if scraped or scratched.
I realise that you would still have the vapour seal to achieve.
I think there are reflective paint, I think it's called Chrome paint, but I'm not sure how effective it would be, though it will certainly reduce the absorbsion rate. However, since it's so reflective I think around the world it's actually illegal for use on vehicles because it's reflectivity can cause accidents (by blinding people)
We've heard some people considering the use of reflective paint on the roof for the same our, that was it's only helicopters and pigeons that will suffer the shine - the only issue with the paint (other than the possible illegality) is that you'd need to keep it clean all the time as dirt reduces it's efficiency
@@FreedomStrider Another question: I have seen on another excellent van build channel (HughTube) the use of automotive carpet, which seems to offer a vapour seal plus (possibly) sound (vibration) insulation and - I assume - SOME heat insulation.
I am wondering whether this is a candidate for ticking all the boxes in one go, and avoiding the need for air gap, albeit not as effectively as having the various separate layers.
You could still add an interior wall or at least battens to attach cabinets and so on to.
The only automotive carpet we can think of is the 4-way stretch carpet that most cars are lined with - it's what we used on our headliner. These carpets are not an all in one solution. I would say, they do help to dampen the vibrations and they do add a little insulation (though not enough to keep you warm in winter.
As for the vapour seal, unless the carpet you are thinking of has been lined with reflectix or another non-breathable material on one side, the fabric itself is very much breathable, so it will not stop the vapour getting to the cold van metal. We are actually planning to use some stretch carpet to help us circulate the moisture in our walls.
And for the radiancy protection, if there is no reflective surface (installed with an air gap) then that will not be covered with an automotive fabric either.
The only way I can think of a carpet starting to be functional is if the carpet has been stretched on a non-breathable, reflective surface, and then that is somehow attached to the van's framing (leaving an air gap on the back). That will sort of, tick the radiancy protection, a bit of the moisture barrier (but not fully) and the fleecy fabric will be a bit insulating. However, there are a lot of red flags that would need resolving down that path. 🤔🙂
@@FreedomStrider Thanks for a great answer.
I’ve always thought that having a white van (as opposed to an expensive dark colour version) was the first thing to consider and reflective covers for the windscreen and side windows in the cab make a massive difference as soon as they are put up on even a U.K. sunny day😉 Ventilation via a roof vent is also key to keeping condensation at bay. Your explanation of conduction and radiant heat was great but don’t forget convection! Warm (damp) air rises...hence the roof vent idea!
I am not sure why you are saying that it will reflect heat both ways? For it to reflect heat both ways, you need to have an air gap on both sides (although the 'fluffy' type insulation would considered like 'air', right?). If you stick it to the metal of the van, it will only reflect the heat back to the van.
If you stick it on the framing, it will reflect the heat back to the insulation of the outside.
I 'feel' that the best way to use Reflectix, is to put it AWAY from the van wall. Because it is easier to warm a van during winter than to keep it cool during summer (provided you have good insulation). What would you say about that? Your feedback is welcome! How did you end up doing it in your van?
And do you really feel that it's better to use Reflectix, instead of just adding more insulation, where the air gap is supposed to be?
As a general rule, whether you put the reflectix on the wall of the van or away from the wall - as long as you have the air gap on one of the sides then results will be the same. The video that explained it best to us is this one, the guy explains it visually very well: th-cam.com/video/E1IwS0_lpBc/w-d-xo.html
The positon of the air gap, making no difference, the way we decided to put it on the van, was a decision based on other practical considerations. How easy is the reflactix to attach, How would we attach the cladding afterwards, What if we need to add framing... etc.
As for adding extra soft insulation instead of reflectix (without doing the maths we can't be sure and we haven't experienced it to compare), but we are very happy with our insulation set up. As soon as we put the reflectix on, the climate in the van became much more balanced, even just us being in the van warmed the space up in winter (enough not to shake with cold). So, if we were to do it again, we would put reflectix on.
Oh, and the 'fluffy' insulation does not count as an airgap - the gap has to be empty air/vacuum
hey, are you not afraid that you have humidy in the isolation ? after some couple of years you will have a lot of rost ..maybee...
Well it is something that is quite unavoidable, if you were to use spray foam insulation and do it properly you might be able to eliminate moisture from your insulation cavities, but must vans have natural drain holes in the walls so the vans walls won't be air tight and moisture can still get in.
The rigid PIR board should eliminate most moisture held in the walls (compared with rockwool which holds a lot more moisture), and with the drainholes unclogged at the bottom, moisture should be able to pass through. Due to the design of vans (being metal), they aren;t really designed to be insulated or have big temperature differences, so you have to do the best you can. Eventually, yes, moisture in the walls will cause rust but then again, regular vans condensate moisture on the inside of the metal walls on hot and cold days anyway, and with insulation taking up the majority of the space inside the wall cavity, it should help somewhat :)
Hello thank you for your video what if you are using 100% Havelock wool does it make a difference
I'm not sure, Havelock wool is New Zealand sheep wool, right? We haven't used it to compare. Things to consider, however, is the weight, smell and if the natural material is an irritant. Otherwise, I'm sure it will keep you warm.
Reflection means it reflects light for instance in a window it will reflect the sun away,if it's inside a van it might as well be plain old bubble wrap.
In the use case in the video, the Reflectix reflects infrared heat as well as light. The fact that you see it reflecting the light when exposed, doesn't mean that (when covered) it will lose its ability to bounce the infrared radiation. Infrared waves are not visible to the human eye, they are experienced as heat. That's why you need the air gap, when installing Reflectix as part of an insulation system, to allow the infrared radiation room travel through the air. Otherwise it will just conduct in and out.
I really love you guys , very informative
Our pleasure!
Very informative video, so helpful. I'm at this stage now and struggling to decide. When you were describing it not being possible to create a complete air seal I thought you weren't going to install a vapour barrier but then you went ahead and attempted a vapour/radiant barrier in one (not criticising here!). I'm swaying on the side of no vapour barrier, if I therefore mount the relextix a few cm's offset from my pir board/bottle wool insulation would this provide a radiant barrier but also provide an opportunity for the insulation beneath to breath underneath / condensation dry? Assuming I would get more condensation beneath insulation but also will provide more chance for drying out. What a nightmare. I'm just scared of effectively trapping condensation! Thanks ☺️
The reason we went ahead with the reflectix despite the moisture trapping issue is because we decided that the radient property benifits of reflectix outweigh the rather poor vaper barrier options. So we installed the reflectix and we did our best to cover as many moisture entries as we could, and we definately saw a noticable difference in the insulation quality after installing the reflectix.
When doing this type of insulation, you will always have some moisture trapped behind the walls.However 1) Ensure that there is no exposed metal, because that is where condensation will form. 2) If you put the reflectix on with some care, the moisture will be very little, so it will rarely cause an issue; leaks from any holes you drill are far more likely to cause rust and need repair.
Also, installing your insulation on a cold, dry day without heating the van, would trap the least amount of moisture behind the walls, pruley because colder air has less moisture (obviously if it is foggy or raining, slightly different story)...of course your figers will be frozen and you'll need about 10 layers on but hey..options😂
Another thought, depending on your budget and if you've already bought some of the stuff or not, one way to eliminate the moisture issue the most effectivly would be spray foam insulation, Because the foam coveres every nook and cranny, no moisture can be trapped behind. We looked it up, if we were to call someone to come and do it, it would have been £1000 (so over double the insulation we've done in our videos).
Far Out Rides has a great section all about this if you’re still planning your insulation. They went for thinsulate and then EZ-Cool (now Low-E Insulation) over bare metal like the frame. Low-E and Reflectix are similar but Low-E has the added benefit of containing some insulation alongside the reflective Vapor barrier.
Hey both, great video! I was wondering... If indeed I can't afford to lose width-wise space in the sleeping area of the van, but could elsewhere, would it be worth installing a radiation barrier in just part of the van? Like the roof, and perhaps parts of the walls? Thanks for sharing your thoughts!
So I assume you mean you aren't going to install insulation in the part where you'd be sleeping width-ways? You can do partial reflectix - but you have to be careful because if your reflectix is not airtight, that will let some moisture in behind the walls, but it will also trap it there, which can cause problems. If you choose to go with partial reflectix, if you just do it on the ceiling, that's probably the easiest to isolate as the cavities on the ceiling are not as connected as the walls. You can do it on the walls as well, but I would recommend thinking about how to seal the edges of your reflectix, or ways that you can ventilate the walls so that the moisture that does enter, can vent out. I hope this makes sense 🙂
Well explained, good on ya :)
Cheers 🙃🙂
wow amazing video. bless you guys
Thank you 😊👍
Is ripping your insulation the best way to create an air gap? Wouldn't it be better to just seal it up as tight as possible and get wider studs(framing) to create the air gap?
Ripping which insulation? The soft one? Can't quite visualize what you are describing... can you give us a bit more detail of what you are thinking? 🤔
@@FreedomStrider yeah at 9:15 you rip the soft insulation to create your air gap
Ah I see what you mean. We ripped that so it would fit in the cavities, the fluffy insulation isn't a substitute for the airgap, our airgap is created by putting the framing over the top of the reflectix (shown in one of our later videos)
@@FreedomStrider oh ok thanks for explaining to me!!🥴
Thanks for the great info guys!!
How do we feel about adding reflectix to polyiso board? I was thinking of attaching reflectix directly to van walls, then half an inch of dead space, then another layer of reflectix adhered to one inch of polyiso, then plywood wall.
How do you see the moisture situation going? I live in a hot area so I feel like most moisture would evaporate within 24 hours, specially with the half inch of complete air flow in the dead space.
Thank you for any help!
So from what I understand, you are not filling the wall cavities of your van with any insulation? If that's the case then that is not a bad way to deal with the moisture on the van metal, as you'll be leaving all the natural vent holes of the open. Also, you are right that in a hot climate the sun would dryout most things quite quickly.
However, leaving the cavities empty and then doing the PIT board on the outside, would reduce your living space... so twist and turns 🙃
In the dead space after your reflectix, is that where you are putting framing? I'm just thinking that if your cavities are empty then you don't really need another air gap.
As far as I can visualize, your insulation system is fine, it will work, and it could potentially manage the moisture more effectively than stuffing the cavities.
Hello, thanks for the video, very informative!
I'm building a catering van and want to keep the heat to a minimum so that the commercial drink fridges don't work so hard to keep things cold. What do you think about styrofoam as an insulator? The problem I see with the fluffy insulation you used is that it can hold water in it if water gets into the walls of the van.
Styrofoam is not as good an insulator as some other options. If you're going to go with rigid insulation board in the walls, I would go with PIR insulation, it much better than styrofoam, though do be aware that shaping any rigin board in the smaller cavities would be nearly impossible and require a lot of patience.
Now budget dependant, the best insulation that you can go with is spray foam insulation, especially if moisture is a concern. This will definitely not trap moisture in the walls, and condensation would be only around the windows, not anywhere within the walls. 👍
Best explanation out there . But the cat stole the video
She always does, we spent so long trying to coherently explain reflectix that she got hungry 🐈
I'm confused, you said the Reflectix should not touch the metal, but you are sticking it to the metal in the end.
What I am not getting right?
No you are right, ideally it shouldn't touch the metal as that would create a thermal bridge. Ideally you can stick some foam or another insulating material to the metal or on top of the reflectix (once stuck). In our case we actually had ply framing on top of the thermal bridges so a good portion of the bridging resolved at the next stage. But any place that did not would potentially condensate so to improve our insulation system I would stick some foam similar.
Hi, nicely explained 🤓🤓.
Cheers 😎👍
Why didn’t you just use the Reflectix perforated foil? It seems to have the same or better radiant qualities as the “bubble wrap” and it is perforated so you don’t have the same moisture issues.
I have never heard of until now 🙃... do you have a link?
I'm so confused, I thought that if you tape it to the metal without a gap there wouldn't be a break. What about the rib you taped it to? Thank goodness there are professionals for people like me.
Not entirely sure what you are asking... a break in what? the vapour barrier?
So what kind of insulation should I use ?
Depends on your needs. We obviously recommend the recycled plastic insulation and PIR board that we used (links in video description) - though if you have the budget for it, spray foam insulation is another good option because that would fill up all of the little air gaps and kinks, and because all the metal will be covered, you will need no vapour barrier.
Thinsulate if you have the budget.
I'm not seeing the air gap in your installation. Are you saying that the wooden framing is the air gap?
Yes the 18mm ply provides the air gap. You need a minimum of 12mm air gap to make the reflection work.
That alluminum if touch the wall it will be super conducive .
It would be best for the metals not to touch, it hasn't caused any problems we are aware of, but logically next time I would insulate the bridges. 😊
The easiest way to fix moisture problems is use the original full headliner. I did with my Sprinter 12 years ago. Not any signs of moisture damage. The original headliner breathes is a good insulation and sound deadener
What is the original full headliner? Do you mean the hard lining that comes with the van?
Yes the original headliner is the same as you have above your head up front. Some Sprinters have this fitted right through to the back doors, usually the bus with 12+ seats. I found a damaged van at the wreckers and removed all 4 sections. Good luck with your build
Great explaination
Cheers!
Did you guys put Reflectix on the sliding door?
No, we didn't put any reflectix on the sliding door because there isn't enough room to provide the airgap necessary for the reflectix to be any good. For the reflectix to work we need at least a 12mm gap, and the sliding door passes quite close to the van's body as the door opens so there isn't that much clearance to have the air gap and then the cladding on top. (each van is different so you do need to check, but that's why, and it's not worth it for the moisture barrier). 😊👍
I did my insulation and vapour barrier the same way as you for the same reasons.
Have you done your curved cab roof yet? As its a complicated shape i did mine with the space blanket insulation. The foil kind with 10 or more layers and can be shaped into all the curves.
Over the cab, with the headliner shelf - we put soft insulation and then reflectix and then stretch carpet - thought the reflectix is not there for radiancy, but mainly for structure. We couldn't figure a simple way of creating an air gap in such a curvy space with our shelf design, however, if we hadn't removed the headliner itself, we could have stuck reflectix on the back of it. That would have created an air gap between the metal and the headliner but it would have skipped the soft insulation. 😀
@@FreedomStrider cool that layering should work aswell. I find some common sense goes a long way with adapting your insulation as long as you stick to the important points.
@@FreedomStrider Do you think that the way that you did is insulating more than the way with sticking reflectix on the healiner(if i do it this way is it going to be better to also ad some more soft insulation or just leave only the reflectix to do its job)
The way the headliner insulation is done is the wrong way to use the reflectix (we did it before understanding it fully). The best practice method for insulation is the way described in the 'reflectix' video - with an air gap. The no air gap in the headliner video, that negates the radiant function of the reflectix, but the soft fluffy insulation will still work as it should. If we were to do the headliner again, we'll either, skip the reflectix or work on an air gap. 🙂👍
@@FreedomStrider Am i right that the more airgap there is the more it is actually insulating therefore you can leave a lot of air gap if you stick the reflectix to the headliner without using soft insulation. Will this create more insulation properties than if you fill it up with soft insulation?
Thanks so much, y'all.
Any time!
I may be wrong, but, you're radiant barrier or reflective barrier, reflects on the side of the air gap only. So you are not reflecting outside heat
No, it will stop the radiation heat transfer both ways. I could write an essay on this 😊, but I think this person demonstrates it well: th-cam.com/video/E1IwS0_lpBc/w-d-xo.html
Very good video helpful.
Thank you ☺️ we are glad it has helped you
What about wiring for lights and plug in stuff doesn't it break the barrier?
Only if you try and put them under the barrier (deep within the walls). Most of our wiring is either above the reflectix or externally mounted in decorative conduit... Though we have run some conduit through the walls for a few if them. So if there are breaks in the barrier from wires and such, you just have to do your best sealing the perimeter before closing the wall up.
Very informative thanks
😊👍
Excellent explanation of radiant heat but a huge fail on how to use sprayed adhesive. Hope you figured out eventually!
Failed how? The adhesive stuck the reflectix perfectly.
@@FreedomStrider Hi, these adhesives work differently than the usual suspects. They need to be applied on both materials then you need to wait until it's dry to the touch and only then press the two materials together. Unless you used a very special one I don't know about, which case I stand corrected.
Awesome work anyway, thank you for sharing and taking the time filming and editing it. I just started mine, hope you are enjoying yours!
nice one you two good vid
Thanks 👍 🙂
Thank you! ☮❤🕉
You're welcome ☺️
It probably shouldn't be right on van metal itself ? I would have rather gone with a strip of wood or something else then the reflective ..
There shouldn't be an issue attaching it directly to the van metal since there is a layer of bubblewrap inside the reflectix between the 2 shiny surfaces, which means it doesn't quite conduct the heat. That being said, if you were to just use the foil aluminium tape, stick that directly to the metal, which then produces condensation. So the bubblewrap reflectix you can stick to the metal, but the foil tape, it's best to avoid it. 👍
As we said in the video, you can put your framing first, then your reflectix. But depending on how you're mounting stuff, that may make it harder to create a full vapour barrier.
You don't need an Air Gap with Reflectix.. You can test this just by putting it on the outside of any windshield. See how much heat or cold is reduced from one side to the other. When the Sun comes out. It's minor with 5mm thickness double sided foil....
Whether you put the reflectix on the inside or outside of the windshield you still have an airgap on one side. Radiant heat is only transferred through air or vacuum (otherwise it is conduction heat transfer), without the airgap the heat will get absorbed and conduct rather efficiently.
@@FreedomStrider It matters a lot. As Reflectix has a builtin air gap to start with..Between both sides of the foil..
And like I said. Go validate it. Just cover the windshield. Inside and out. You will see the differences. As both sides will be touching the surface of the glass... The one on the outside test vs the one inside.
I will wait while you go test it. Then tell my your findings.
The gap between the reflectix is proof that it needs space between to create the R-Value. Installing it correctly with up to 1/4-1/2 inch gap away from the heat source will give optimal R-Value.
@@R.L.U. Did you not read my post? I said it has it's "Own" air gap. You don't need any additional Spacing. Just go Validate it with a thermal gun. It makes no difference..
@@WizzRacing Sorry but you are wrong about that.
First of all, there are different types of reflectix, for instance small and big bubble foil, woven foil and metalized foil. second: you MUST have an air gap to avoid conductivity with other objects, third: there is actually a sweet spot when it comes to an air gap, which might also be different depending on the application it is used for.
I won't spoil all the details for you but you should read this paper about it: frsb.upm.edu.my/upload/dokumen/20191004083717Paper_3.pdf
Also I recommend watching these two video's specifically:
- Proof that foil radiant barriers don't work without air gap: th-cam.com/video/aU4q6RKaOQQ/w-d-xo.htmlsi=bM1QYCp2kSjvhISY
- Proof that an air gap is required: th-cam.com/video/TdPLmbkhH2o/w-d-xo.htmlsi=IHL7fEXcTXplskVI
I must add to this, that for windows an air gap might not make much difference, because glass is not a good conductor of heat, reflectix applied directly to glass may not have as significant negative of an impact as it would on a material like metal (inside a van in this case).
Another important note here is that when applying reflectix with an air gap on the outside of the van (metal | air gap | reflectix | insulation | wall), you must make sure that the heat can escape between the metal and reflectix. I haven't read much about this but I feel like the hot air might get trapped leading to a negative impact. This is basically the only reason I can think of not adding reflectix apart from the existing vapor barrier issue it might cause. If anyone has more information on that topic please let me know.
right so i wasted £50 on bubble wrap and silver tape and now i've locked moisture in so my van will rot and I lined my van in carpet today before watching this video so too late to remove it haha never mind i know for next time!
You've locked in as much moisture as we have, so your van will not rot, don't worry! All you've lost is the radiant barrier benefits (so the airgap). We all live and learn, we did the same as you on our headliner before we understood the science. 😊
Ah yes the worst part of building a van! It was the best day of my life when we were done with reflectix. Never again!
Also guys have the door open when you use that spray fix, cancer is real! Look on the back of the can.
Also did you say you are using 18mm ply for your walls?
Actually doing the reflectix, not actually too bad. Researching how to install it correctly and why...fair point 😂
I agree with about the spray glue, we did have the back doors open with that stuff.
At present we are using 18mm ply for the framing, not the actual walls (the walls are going to be 3mm poplar ply) 😊
@@FreedomStrider ah ok I was gonna say 18mm is a bit overkill for walls! I used 9mm and that's quit heafty. Have you started the framing yet?
Not just yet - hoping to this week, though it quite a busy one.
@@FreedomStrider What is the difference between poplar ply and the normal ply?
Poplar ply is made of a different type of wood, so poplar is a softwood, whilst the hardwood ply that you find in most store can be made from birch, beach or spruce (I can't remember which - it varies per region and country). However, they are usually hardwoods and as such are double the weight. (e.g. 3mm hardwood = 2.3kg per m2 vs 3mm poplar softwood = 1.2kg per m2).
However, poplar is less structural (even when thicker) so if you are to build a bed or a chair, it is structurally recommended to go with hardwood, but weight-wise, poplar is best. So you have to compare and compromise, depending on needs. 🙂
No good van builder uses reflectix anymore. You should’ve known better.
As long as you use it correctly with an airgap, and have considered how to vent your walls, which we have, then it's fine 👍
Cute lady.
;)
Terrible!
noted.