My dad is an architect who has designed symphony halls. He said that using resilient channel on both sides of a single wall provides more sound isolation than doing double walls. It comes up several times a year often in conversations.
Thorough AND concise - super easy to understand for us lowly non-builder-annoying-homeowners. Never heard of the Intello wrap; very cool concept! I also never considered the idea that more insulation isn't necessarily "better" in terms of cost/benefit, and that computer program you used really helped illustrate that. Thanks so much for making these videos!
It is "better" it's just a question of diminishing returns, and by doing the big things right like a continuous layer of exterior insulation the rest doesn't matter so much.
For the tubs, put some wet concrete under where you stand, it give a much more solid surface. The gap is often about 3 inches, so don't just put a mound of concrete, also put a few inches of rigid foam under the concrete lump so that after it has wicked out the heat from the tub, it stops trying the warm the floor.
7:43.. I’ve heard this contention... my real life experience on this. I loosely and incompletely filled the walls of my shed workshop. Had one whole wall uninsulated (and I could feel it sucking at me when I was close to it.. there were gaps in the batt.. some of the batt was safe n sound... others were comfort. Went from two heaters on high and long John’s with a down jacket, to one heater on low and T-shirt. Conclusion, some insulation is better than none.
Energy (including heat) follows all paths, the rate of transfer is proportional to the respective resistance of each path. Increasing insulation on one wall doesn't increase heat transfer through a less insulated wall. It simply makes heat transfer disproportionate, which may or may not be a problem.
I think you are making a point about Corbett's statement "it doesn't makes sense to insulate to different levels in different parts of your home". I agree that it was probably over simplified. Otherwise, wouldn't we insulate our walls to the equivalent R-Value of the windows?
@@JW-gc5ve yeah I'm not trying to be overly argumentative but whether we're talking about electricity, fluid flow, or heat transfer, it's a really common myth that it "takes the path of least resistance." While it's technically true that it does, it also takes other paths. If it only took the path of least resistance then all the lights in your house would turn off when your air conditioner runs. Increasing insulation on one area and not another does not redirect heat from transferring to the more insulated area and cause it to transfer into the less insulated area instead. It may not make sense economically, which he demonstrated, and in extreme circumstances it might result in problematic, incompatible heating/cooling load profiles for areas served by the same comfort heating and cooling system.
@Joel Becker you can clearly demonstrate that heat flow is non-linear with the Assembly U-Factor Calculation. That’s basically what I’m trying to do with the simplification here- normal people do not need to know all the technical details of our work, as long as they understand that a simple ‘common sense’ approach does not work with a lot of the dynamics in their homes.
Just a tip. Change that pex you have for your potfiller to a drop ell. Most pot fillers mount like a shower head IE threaded onto a 1/2" pipe which also provides the support for it. Easy fix now VS later. Ad for the Intello I'm hesitant to use that in a house that is in a primarily cooling climate. I like the idea but a little leery of it. Seen way too many moldy walls from having a moisture blocking barrier behind the drywall. Fine in a house that dries to the outside up north though. Sealing outlet boxes should be code IMO. Few realize just how much airflow there is through them especially on older unsealed houses. When you mount your nail plates you want to use a router to notch the lumber for it so it doesn't make the drywall stick out. Allot of work but it does make a difference in flat drywall and stopping airflow between cavities and from the room to the wall. Also to add. Stopping the airmovement as well as you have also stops vast amounts of sound transmission as well.
@@HomePerformance Gotta do some more research on the intello before I will use it. Just wary right now. I think it would be extremely useful and effective on remodels where the existing structure leaks like a sieve.
I will need to check out your prior videos on Intello because I am unfamiliar with the product. I am working through the building permit stage. The plan is to aggressively work to minimize air infiltration. Most of the plan relies on Zip sheathing, tape, liquid flashing, minimizing the number while specially treating any penetrations, and using AeroBarrier. I had not considered a second barrier on the interior walls.
I am not to the stage you are yet but it is funny that I am thinking of doing the same thing when I start building. Zip (or equivalent), tape/liquid flash, and aerobarrier after its all done... for added peace of mind
To be precise, I don’t recommend spray foam if there’s another technique/product that will work. But if you must, then ask the foam manufacturer what thickness they guarantee as an air barrier.
I have subscribed to your channel 👍☺️🇨🇦 and shared this vid with a senior couple thinking of building a new ranch style, downsizing. Thank you for taking the time and care to show the detail and building science of what you are doing. As a DIY'er I am learning a lot from you and bookmarked some of your vids to help me prep for a large and high extension to the existing home. Yes, I do plan to separate the 2.5 high, ICF basement from the existing 40 yr old home. The only connection is the porch area so I am thinking a double pane patio door since I need to be able to see the spacious area that is meant for the pack of dogs or when the next family purchases it they may want to be able to see the "teenage party" going on in that sort of "rec room" space. Lots of really good smart info and congrats on all your success with your build and growing YT channel. 😊🙏🇨🇦
You mentioned no wanting hot and cold rooms, and being in atlanta. I am in Mobile Alabama, in the summer it will often start raining out of a cloudless sky because the humidity became a bit too high. When it is a non-condensing 100% humidity, and 106F, sweat does not evaporate to cool you. I was planning a mud room which may be excessively cold that I will be able to go into periodically while working in the yard to ward off heat stroke. It may have a window unit just to be extra cold.
I hear you Mike- but try making it dry instead, with a fan to blow on you. Lower the temp of your skin and you’ll have MORE moisture condensing on you, making you even hotter.
Excellent built! I the interior airtight membrane twice in high performance house. Imagine having a 0.1 ACH@50pa + having your Intello membrane = 0.005ACH@50pa (I think the world record is 0.05ACH50pa). Here in Quebec, Canada, we use furring strips 1"x3"@16" on the interior side of the wall. My suggestion : Double furring or "furring strips" 2"x3"@16". With that you have 1-1/2" of clearance. What I understood with life, that it's better to use Aikido. Let it flow as a Khun Fu monk.
I get it, so why not just frame the entire structure as 2x6 instead of having 2 random locations at 2x4, which caused you to stick with r15? Basically you built 80-90% of it as 2x6. Why not just complete it all as 2x6, thereby making the engineer happy while also keeping equal consistency throughout the frame, allowing for more insulation consistently throughout the build?
My wife drilled a hole in the bathroom to hang a towel rack. She drilled right into the breaker box on the other side. Thankfully she didn’t shock herself! It did cost me $600 to fix her mistake though.
I put 15cm rockwool in my bedroom floor over the living room for sound and ever since the room and floor is terribly cold... I am considering removing most of it and use something that "only" stops noise
The modeling is correct, but the lack of significant difference is due to diminished returns of insulation, not the presence of lower insulated R15 int walls. For your mild Atl. climate your R15 int. + R8 ext. is already deeply into the flat part of the diminishing curve. Under these conditions, adding more insulation on top simply has insignificant impact, but that impact is divorced from your inability to evenly insulate to that value. Therefore I must strongly disagree with your explanation that the insignificant difference is due to heat following the path of "least resistance" and all it implies. However, while still agreeing with the messaging to model and use science to drive your decision making process. Repeat this model but put R23 on all walls, you won't suddenly get a significant difference now that you eliminated "the path of least resistance". To punctuate further, your windows are
Home Performance is one of the best channels on TH-cam! We are learning so much planning our remodel. Great timing! We do have a question if you could. What are the windows we saw that were small squares, maybe about 1' - 18" ? and and what height did you place the in wall "next to toilet" vent? Genius idea we HAD to include but are lost on the #'s. Care to share that detail or dims? Thanks for showing us the properties of Rockwool and INTELLO.
Aw, thanks Kevin! So glad you found us. Yes, those are 12” square fixed windows, same Alpen brand and specs as everything else in the house. The vent I put ~3” above the top of the toilet, so about 36” from surface of subfloor. As long as it’s below your face, it should work.
so much extra work. Just build the internal walls out of a solid structure like blocks, bricks or monolithic walls. Then you can build the external walls out timber frame with insulation in between the timbers and a continuous insulation outside or glulam beams with insulation acting as the non load bearing external walls effectively creating a hybrid timber structure that’s the best of words, easy and safe internal walls for structural support and higher insulation values in externally without the hassle of solid walls and the tricker insulation work.
Receptacles by code are every 12 feet. You must be able to reach an outlet from 6 feet away. Its a tricky one. Its all up to interpretation. But they definitely specify here. At least the NEC does.
I understand when Corbett’ uses the phrase "heat using the path of least resistance" however I believe he's not quite correct. According to Building science Guru Joseph Lstiburek, heat always goes to cold, and while I'm no expert in thermodynamics. Joe is. I may be a nitpick but could you clarify?
I'm a fan of your channel and love most of your ideas. Hiweverm the Intello Plus one you present here is horrible. You've essentially created a cavity in your studs to trap moisture. This is going to induce mold growing in your walls (see Risinger's video on this). To do the belt and suspenders correctly, you should've installed the intello outside the studs (i.e. underneath the sheathing). Or rather, follow Martin Holladay's advice and don't install any. On the positive side, given that you've air sealed your sheathing well, I don't anticipate this being a huge deal as you'd need the air to actually travel into the cavity to create problems. Though I'd be interested in knowing what the inside wall looks like after 100 years.
Actually, no- the intello is vapor open (up to ~100 perms). It’s always risky to put impermeable layers into the assembly (like ZIP, for example), but you see builders do it all the time. There are no impermeable layers here- even the ForceField WRB is 3-5 perms.
@@walktxrn is it tho? The process of making them is extremely similar, the characteristics of them are the same, under a microscope they even look similar. Also asbestos isn't 1 material it's more of a category of cotton candy like rock.
Funny enough, we visited the Harvard or MIT mineral museum, and I asked if and where they kept the asbestos- the receptionist said ‘gosh, I hope we don’t have any’. ;D Asbestos is pretty cool. I found it after looking for three minutes.
I see you have recessed lighting, care to share which cans you went with? I am building a home with a vented attic and recessed lighting has me paranoid. I have done so much work on the walls, windows and sealed crawlspace, I would hate for a dozen or so lights to ruin it all.
Hey Aaron- those aren’t recessed lights actually, you are correct that they suck. We have junction boxes made airtight which we’ll put LED puck lights on, resembling recessed lighting at a glance but very different in performance impact.
Hi Corbett, I'm just now getting caught up on this video series and have this question: if I'm understanding you correctly, you've got a 3.5" R15 batt in a 5.5" exterior wall cavity, leaving a 2" air space between the batt and the interior sheetrock. I know that with a lower density material like fiberglass, convective looping within the cavity would reduce the effective R value by a significant margin. Is this not a concern with rockwool due to the higher density? Does your energy model account for any impact created by this air gap? I've always been taught to fill the cavity when air permeable insulation is used. This is fresh on my mind having just read through John Straube's "Thermal Metrics" paper. By the way, here's an excellent pun from page 13 of said report: "However, as some airflow always does occur, the impact on thermal performance is hotly debated." Thought you might enjoy that.
Thanks Nathan, and Straube wrote the foreword to my book. Air gap on the interior is not a problrm, since temps are all the same inside the insulation.
Thats a lot of insulation! Haven't made it through the whole video... but what are your thoughts on spray foam in an attic? Both of my HVAC are in attic so I would need combustion air for that and water heater
Combustion air does NOT have to come from outdoors, so encapsulating your attic may not be an issue (as you know, I’d recommend you test it before, after, and during). Spray foam is not a favorite of mine because of flame retardant offgassing, but if you ventilate properly and don’t spray everywhere in the house you can do it well.
If I am not wrong: Intello for indoors is a vapour layer to prevent vapour diffusion from inside to the outside. And Zip is also a vapour layer (also as WRB,...) to prevent vapour from outside to go to the inside? However, the Zip board allows passing vapour from the inside to the outside. Am I correct?
Intello is an air barrier that works in both directions. It allows vapor diffusion (drying) when humidity is high. The direction depends on the season.
so if part of the house has holes not putting hole in the rest of the house doesn't improve heat loss? Insulation is like hole less insulation the bigger the hole the more the smaller so not having holes doesnt help? Obviously theres a return on investment concern but that's not the same so if you have multiple points of least resistance you have more heat loss, ,ore heating coosts.
Hi, great video. Can you tell me the software program you are using to calculate the insulation values? I am also trying to design the insulation values for our new build next year to help determine what levels are best.
Won’t happen- since the airsealing details are in place you’d need pure vapor diffusion, which just doesn’t move enough moisture to do anything. Airsealing is the way to stop condensation anywhere but Alaska.
Michael Murphy if you wear a plastic poncho in the rain you will still get wet if you are covered in a gortex fabric you will stay dry as it allows air and vapor to pass through were as plastic traps humidity.... at least that’s my story and I have used gortex and plastic ponchos many times
My wife and I are about to embark on gutting an existing 70s 2-story house, and "remodeling" into a single story home office/gym which will be well sealed and insulated. At about the same time we're building a small, near passive house. Your videos have been super informative. Question on the electrical outlets. Seems like a quick couple of shots of an expanding foam sealant would be far easier and quicker than the butyl tape. Did you consider that? Also, is the space above the ceiling rockwool vented?
Foam cracks snd degrades differently than this tape over the years- we aim for this to be a 100-year house. And the ceiling cavity is not vented, no need. No moisture will accumulate there, because of the interior wrap and all layers vapor permeable, plus in Atlanta the temps are fairly mild.
So I am a bit confused. If you already have a continuous air barrier on the exterior, why put this Intello on the inside of the wall? I know it is a "smart" vapor barrier, but it seems like you are just creating another obstacle for any moisture that might get in the wall from drying to the inside. Plus, the drywall itself is somewhat of an air barrier, which means you will now have three different air barriers, which just seems unnecessary. Is there some benefit to this that I'm missing?
It's a barrier for air, not moisture. The main reason here would be that there is a vapor impermeable radiant barrier blocking drying if any moisture gets into that area above the rockwool. So you really don't want moisture there at all and drywall + Intello gives you a good probability the whole house won't fail.
Is there any way you can specify your wall detail on the shed style roof where the two walls meet at the top. Im wandering how the walls meet with one being straight and the other wall being sloped. Did you put a angle cut on the top of the sloped wall where it will meet the top of the other wall which would be the top corners or is it cut square where it would leave a small gap between the walls.
You angle cut the roof rafters where they rest on the lower wall. It’s in the roof framing vid- search roof on our channel, you’ll see exactly how we did it
@@HomePerformance Oh ok. Cool I missed that video. Will have to check it out. Thats what I was thinking how it was done was to angle cut the framing where the two walls meet. Thanks again. Enjoy the videos.
Why would you use a fiberous insulation beneath the slab? It will lose R value when wet, which it will be. Also, seems it could breakdown over time due to biologics and dampness, whic ridgid foam will not.
Question concerning your comment at time stamp 13.30. You mention that the electrical code states that outlet in exterior walls need to be every 6'. Is that a local electrical code? National Electric Code 210.52(A) states "A receptacle outlet must be installed in every kitchen, family room, dining room, living room, sunroom, parlor, library, den, bedroom, recreation room, and similar room or areaso that no point along the wall space is more than 6 feet, measured horizontally along the floor line, from a receptacle outlet." This means that outlets can be installed no more than 12' apart ... The 2 outlets are no more than 6' from any point that exists between them.
@@HomePerformance Thanks for clarifying. I'm always curious as some states/cities have code restrictions that are greater than the national code. You gave really good explanations concerning different wall insulation levels. That software package is a great way to help keep a project on budget.
Hi Corbett, could you tell me if your skillion roof is vented or unvented, building a house with a skillion roof this summer, in northern Quebec, Canada, and wanted to do an unvented with Intello plus and Roxul but was thinking of filling the cavity btw the i-joist...? Would really like a side cut of a good set-up thx!!
Unvented, 5” gap on top. Would NOT recommend for your climate, Dan, you’re dealing with very different temps up there. Filling the cavity sounds good. If you’re nervous you can use Lstiburek’s vapor port detail as well.
@@HomePerformance Thx! So i would go unvented with Rockwool completely filling cavity to top, and Intello plus inside, would you still use a osb with barrier in my case? Appreciate your feedback!
What's up Corbett? In NC, so far planning to fill my roof cavity with blown in cellulose and intello, 14in cavity. Had zip scheduled to go up on the deck but been toying with the idea of a Adhesive skin and plywood to allow the I joist cavity to dry to the exterior and rain screen under my standing seam. Any opposition?
For residential? There a ton of BPI certified home energy firms. There are high-performance builders like Wolfworks. For commercial Steven Winter & Associates?
Actually its 5 inches solid when wrap insulation outside. Comfort board 110 5 inches thick r 20 over cmu block with vermiculite cores. Air gap r 2 and masonry veneer. Canadians usually vapor barrier inside of house. Not only do they tighten head bolts twice but also put and a certain angle extra of tightening. We use low perm wraps to keep moisture flowing out. Yes it does make sense to insulate at different levels. Too much insulation will trap condensation. Or like people spray foaming rim joist pockets creating moisture pockets. Or people trying to use fiberglass around doors and windows. The term we use is educated idiots. Looks good on paper but real world moisture problems happen. Moisture in air tight houses should be addressed. Kitchens, bathrooms, rim joist pockets, basements, and around windows and doors.
At 10:00 where you explain how overstuffing walls yeilds little improvement in performance. Your example is confusing to me because you seem to be saying that its not worthwhile to have great variation in wall performance in a simgle building but your example seems to show that stuffng more insulation than can fit into the wall cavity will yeild little improvement in home performance. I dont think anyone who understands the basics of how insulation works would overstuff wall cavities with the belief that the more product you stuff in there the more insulated the wall would be. What we really want to know is how detrimental is it to have a wall,/door/ceiling that's less insulated im an otherwise highly insulated house? Not every house is a new build and some insulation improvements like 1" exterior foam are low hanging fruit while others such as triple pane windows are much costlier.
I am close to building in the ATL area soon. From your energy analysis, would this also indicate that there is no real advantage to going from an R15 2x4 wall to an R23 2x6 wall? For some reason I thought I had seen an analysis that showed you are on the "flat" part of the curve at this point. I plan to install an ERV system to complement what is hopefully an airtight house using Zip and AeroBarrier.
@@jneilcopeland are you in a hot humid climate? Two things. 1. I'm not a big fan of zip sheathing. It's osb and you should read what building science corp has to say about osb - not good and plywood is much better. But did you know you many not even need sheathing? If you are using stucco you can use it without sheathing-no osb to rot away or get mouldy and it saves money too 2. In a hot humid climate vfr is generally not a good idea. It can and will reduce the flow low enough that the coil is not colder than the dew point.ie it maintains temp with no dehumidification which is a bad idea. If some one tells you to get a dehu they should also tell you that a dehu can consume up to 10kwh a day, which could be up to 1/3 of your energy consumption
@@jl9678 Yes, I will be building in Atlanta. I live in a 20 YO house that I consider very drafty and desire to have a tight home going forward. What would you recommend as an alternative to Zip, OSB, and stucco (which wont work for the aesthetics of my home).
I fundamentally disagree with your approach to remove plastic from your home + allowing any moisture to travel into your wall. I will however admit that most of everything else you say is spot on.. Perhaps the difference is I'm in a much farther north climate. So it might be climate differences. Code won't even allow semi-permeable membranes (like Intello) here.
Right on- I always try to include the exemption ‘unless you’re in Alaska or Miami’ to that plastic bit. Anywhere there is more than one season, plastic is in the wrong place in the assembly half the time.
You want your sleeping spaces to be cooler than your living though. Especially with women. Just saying my frustration when she turns it down to 60 at night then opens a window to heat it back up is immeasurable.
@@HomePerformance Right but for both genders you want your sleeping space cooler than your living. Just been my experience if favors one, didn't mean to imply uniformity.
I hear you Steven, don’t worry- but I’ll also point out that most people have never experienced a truly high performance home, and the feelings of comfort and the taste of fresh air do not require bumping tstats up or down or opening windows.
“Keep the women in my life happy” this is the exact same reason I insulated my bath tub! Glad to see you did the same!
My dad is an architect who has designed symphony halls. He said that using resilient channel on both sides of a single wall provides more sound isolation than doing double walls. It comes up several times a year often in conversations.
It's also much cheaper to use resilient channel.
What if you use both?
As an electrician I have to say you marking the floor is great idea! I've dug for many of buried boxes
Thanks for the encouragement my friend
Thorough AND concise - super easy to understand for us lowly non-builder-annoying-homeowners. Never heard of the Intello wrap; very cool concept! I also never considered the idea that more insulation isn't necessarily "better" in terms of cost/benefit, and that computer program you used really helped illustrate that. Thanks so much for making these videos!
So glad you found us, @Nicholas C!
It is "better" it's just a question of diminishing returns, and by doing the big things right like a continuous layer of exterior insulation the rest doesn't matter so much.
For the tubs, put some wet concrete under where you stand, it give a much more solid surface. The gap is often about 3 inches, so don't just put a mound of concrete, also put a few inches of rigid foam under the concrete lump so that after it has wicked out the heat from the tub, it stops trying the warm the floor.
Nice, Michael
Excellent video! Thank you 🙏
I too am a Roxul guy from way back. I like your use of air spaces and keeping R values consistent throughout. Smart stuff. Keep Rockin’.
✊thanks twisted
7:43.. I’ve heard this contention... my real life experience on this. I loosely and incompletely filled the walls of my shed workshop. Had one whole wall uninsulated (and I could feel it sucking at me when I was close to it.. there were gaps in the batt.. some of the batt was safe n sound... others were comfort.
Went from two heaters on high and long John’s with a down jacket, to one heater on low and T-shirt. Conclusion, some insulation is better than none.
Okay, I choose you to build our home, good stuff.
Haha, thanks for the compliment JC! I doubt I’ll be doing this again, but you never know.
Energy (including heat) follows all paths, the rate of transfer is proportional to the respective resistance of each path. Increasing insulation on one wall doesn't increase heat transfer through a less insulated wall. It simply makes heat transfer disproportionate, which may or may not be a problem.
I think you are making a point about Corbett's statement "it doesn't makes sense to insulate to different levels in different parts of your home". I agree that it was probably over simplified. Otherwise, wouldn't we insulate our walls to the equivalent R-Value of the windows?
@@JW-gc5ve yeah I'm not trying to be overly argumentative but whether we're talking about electricity, fluid flow, or heat transfer, it's a really common myth that it "takes the path of least resistance." While it's technically true that it does, it also takes other paths. If it only took the path of least resistance then all the lights in your house would turn off when your air conditioner runs. Increasing insulation on one area and not another does not redirect heat from transferring to the more insulated area and cause it to transfer into the less insulated area instead. It may not make sense economically, which he demonstrated, and in extreme circumstances it might result in problematic, incompatible heating/cooling load profiles for areas served by the same comfort heating and cooling system.
@Joel Becker you can clearly demonstrate that heat flow is non-linear with the Assembly U-Factor Calculation. That’s basically what I’m trying to do with the simplification here- normal people do not need to know all the technical details of our work, as long as they understand that a simple ‘common sense’ approach does not work with a lot of the dynamics in their homes.
Just a tip. Change that pex you have for your potfiller to a drop ell. Most pot fillers mount like a shower head IE threaded onto a 1/2" pipe which also provides the support for it. Easy fix now VS later.
Ad for the Intello I'm hesitant to use that in a house that is in a primarily cooling climate. I like the idea but a little leery of it. Seen way too many moldy walls from having a moisture blocking barrier behind the drywall. Fine in a house that dries to the outside up north though.
Sealing outlet boxes should be code IMO. Few realize just how much airflow there is through them especially on older unsealed houses.
When you mount your nail plates you want to use a router to notch the lumber for it so it doesn't make the drywall stick out. Allot of work but it does make a difference in flat drywall and stopping airflow between cavities and from the room to the wall.
Also to add. Stopping the airmovement as well as you have also stops vast amounts of sound transmission as well.
Thanks for following, and for all the helpful tips, Robert!
@@HomePerformance Gotta do some more research on the intello before I will use it. Just wary right now. I think it would be extremely useful and effective on remodels where the existing structure leaks like a sieve.
I will need to check out your prior videos on Intello because I am unfamiliar with the product. I am working through the building permit stage. The plan is to aggressively work to minimize air infiltration. Most of the plan relies on Zip sheathing, tape, liquid flashing, minimizing the number while specially treating any penetrations, and using AeroBarrier. I had not considered a second barrier on the interior walls.
I am not to the stage you are yet but it is funny that I am thinking of doing the same thing when I start building. Zip (or equivalent), tape/liquid flash, and aerobarrier after its all done... for added peace of mind
Brilliant points. You are a definition of home science
Aw shucks
One question. Do you recommend 1 or 2 inches of spray foam and top it with rockwool?
To be precise, I don’t recommend spray foam if there’s another technique/product that will work. But if you must, then ask the foam manufacturer what thickness they guarantee as an air barrier.
I have subscribed to your channel 👍☺️🇨🇦 and shared this vid with a senior couple thinking of building a new ranch style, downsizing. Thank you for taking the time and care to show the detail and building science of what you are doing. As a DIY'er I am learning a lot from you and bookmarked some of your vids to help me prep for a large and high extension to the existing home. Yes, I do plan to separate the 2.5 high, ICF basement from the existing 40 yr old home. The only connection is the porch area so I am thinking a double pane patio door since I need to be able to see the spacious area that is meant for the pack of dogs or when the next family purchases it they may want to be able to see the "teenage party" going on in that sort of "rec room" space. Lots of really good smart info and congrats on all your success with your build and growing YT channel. 😊🙏🇨🇦
Glad you found us, Meg, keep up the good work
How do you not have more subscribers? Great content!
Aw thanks Matt- please spread the word! And if you get deep enough that you want to join us, it’s very easy:
patreon.com/HomeDiagnosisTV
You do rock so hard, Corbett... rock wool!
Thank you Mr. Cat
You mentioned no wanting hot and cold rooms, and being in atlanta. I am in Mobile Alabama, in the summer it will often start raining out of a cloudless sky because the humidity became a bit too high. When it is a non-condensing 100% humidity, and 106F, sweat does not evaporate to cool you. I was planning a mud room which may be excessively cold that I will be able to go into periodically while working in the yard to ward off heat stroke. It may have a window unit just to be extra cold.
I hear you Mike- but try making it dry instead, with a fan to blow on you. Lower the temp of your skin and you’ll have MORE moisture condensing on you, making you even hotter.
Excellent built! I the interior airtight membrane twice in high performance house. Imagine having a 0.1 ACH@50pa + having your Intello membrane = 0.005ACH@50pa (I think the world record is 0.05ACH50pa).
Here in Quebec, Canada, we use furring strips 1"x3"@16" on the interior side of the wall. My suggestion : Double furring or "furring strips" 2"x3"@16". With that you have 1-1/2" of clearance.
What I understood with life, that it's better to use Aikido. Let it flow as a Khun Fu monk.
Could you use some kind of spray foam or silicone to seal the rear of the boxes and wires? Or is the tape the way to go ?
I get it, so why not just frame the entire structure as 2x6 instead of having 2 random locations at 2x4, which caused you to stick with r15? Basically you built 80-90% of it as 2x6. Why not just complete it all as 2x6, thereby making the engineer happy while also keeping equal consistency throughout the frame, allowing for more insulation consistently throughout the build?
My wife drilled a hole in the bathroom to hang a towel rack. She drilled right into the breaker box on the other side. Thankfully she didn’t shock herself! It did cost me $600 to fix her mistake though.
Ha- damn. Coulda been me about a million times, please tell her I said so. Good for her, hanging a towel rack!
I put 15cm rockwool in my bedroom floor over the living room for sound and ever since the room and floor is terribly cold...
I am considering removing most of it and use something that "only" stops noise
The modeling is correct, but the lack of significant difference is due to diminished returns of insulation, not the presence of lower insulated R15 int walls. For your mild Atl. climate your R15 int. + R8 ext. is already deeply into the flat part of the diminishing curve. Under these conditions, adding more insulation on top simply has insignificant impact, but that impact is divorced from your inability to evenly insulate to that value. Therefore I must strongly disagree with your explanation that the insignificant difference is due to heat following the path of "least resistance" and all it implies. However, while still agreeing with the messaging to model and use science to drive your decision making process.
Repeat this model but put R23 on all walls, you won't suddenly get a significant difference now that you eliminated "the path of least resistance". To punctuate further, your windows are
Home Performance is one of the best channels on TH-cam! We are learning so much planning our remodel. Great timing! We do have a question if you could. What are the windows we saw that were small squares, maybe about 1' - 18" ? and and what height did you place the in wall "next to toilet" vent? Genius idea we HAD to include but are lost on the #'s. Care to share that detail or dims? Thanks for showing us the properties of Rockwool and INTELLO.
Aw, thanks Kevin! So glad you found us. Yes, those are 12” square fixed windows, same Alpen brand and specs as everything else in the house. The vent I put ~3” above the top of the toilet, so about 36” from surface of subfloor. As long as it’s below your face, it should work.
so much extra work.
Just build the internal walls out of a solid structure like blocks, bricks or monolithic walls.
Then you can build the external walls out timber frame with insulation in between the timbers and a continuous insulation outside or glulam beams with insulation acting as the non load bearing external walls
effectively creating a hybrid timber structure that’s the best of words, easy and safe internal walls for structural support and higher insulation values in externally without the hassle of solid walls and the tricker insulation work.
Thank you. Love your channel. Just curious if you’ve heard or ever worked with hemp products for insulation? A sustainable, interesting product.
Receptacles by code are every 12 feet. You must be able to reach an outlet from 6 feet away. Its a tricky one. Its all up to interpretation. But they definitely specify here. At least the NEC does.
Partly why we opted for floor receptacles where the 2x4 exterior wall called for them! Easy workaround.
I understand when Corbett’ uses the phrase "heat using the path of least resistance" however I believe he's not quite correct. According to Building science Guru Joseph Lstiburek, heat always goes to cold, and while I'm no expert in thermodynamics. Joe is. I may be a nitpick but could you clarify?
I'm a fan of your channel and love most of your ideas. Hiweverm the Intello Plus one you present here is horrible. You've essentially created a cavity in your studs to trap moisture. This is going to induce mold growing in your walls (see Risinger's video on this). To do the belt and suspenders correctly, you should've installed the intello outside the studs (i.e. underneath the sheathing). Or rather, follow Martin Holladay's advice and don't install any.
On the positive side, given that you've air sealed your sheathing well, I don't anticipate this being a huge deal as you'd need the air to actually travel into the cavity to create problems. Though I'd be interested in knowing what the inside wall looks like after 100 years.
Actually, no- the intello is vapor open (up to ~100 perms). It’s always risky to put impermeable layers into the assembly (like ZIP, for example), but you see builders do it all the time. There are no impermeable layers here- even the ForceField WRB is 3-5 perms.
Asbestos is an amazing mineral. The second air layering is genius
Rockwood isn't asbestos. Thanks though.
@@walktxrn is it tho? The process of making them is extremely similar, the characteristics of them are the same, under a microscope they even look similar.
Also asbestos isn't 1 material it's more of a category of cotton candy like rock.
I get your gist, @My Cool. I think asbestos is an alarming material for the health reasons is all.
@@HomePerformance it's a subject that needs more attention for that very reason.
Funny enough, we visited the Harvard or MIT mineral museum, and I asked if and where they kept the asbestos- the receptionist said ‘gosh, I hope we don’t have any’. ;D
Asbestos is pretty cool. I found it after looking for three minutes.
Can we reuse commercial insulation boards repurposed for say crawlspace under a log home?
Could you use the intellio wrap on the sub floor joists above my crawl space and on the attic floor of a vented attic?
Yes I think you could for the crawl space. For the attic you would want it on the interior side of the insulation.
When you attach the drywall and punchier the inside house wrap does it matter?
As long as the drywall screws hold pressure around the punctures, it does not matter.
I see you have recessed lighting, care to share which cans you went with? I am building a home with a vented attic and recessed lighting has me paranoid. I have done so much work on the walls, windows and sealed crawlspace, I would hate for a dozen or so lights to ruin it all.
Hey Aaron- those aren’t recessed lights actually, you are correct that they suck. We have junction boxes made airtight which we’ll put LED puck lights on, resembling recessed lighting at a glance but very different in performance impact.
Hi Corbett, I'm just now getting caught up on this video series and have this question: if I'm understanding you correctly, you've got a 3.5" R15 batt in a 5.5" exterior wall cavity, leaving a 2" air space between the batt and the interior sheetrock. I know that with a lower density material like fiberglass, convective looping within the cavity would reduce the effective R value by a significant margin. Is this not a concern with rockwool due to the higher density? Does your energy model account for any impact created by this air gap? I've always been taught to fill the cavity when air permeable insulation is used. This is fresh on my mind having just read through John Straube's "Thermal Metrics" paper. By the way, here's an excellent pun from page 13 of said report: "However, as some airflow always does occur, the impact on thermal performance is hotly debated." Thought you might enjoy that.
Thanks Nathan, and Straube wrote the foreword to my book. Air gap on the interior is not a problrm, since temps are all the same inside the insulation.
Thats a lot of insulation! Haven't made it through the whole video... but what are your thoughts on spray foam in an attic? Both of my HVAC are in attic so I would need combustion air for that and water heater
Combustion air does NOT have to come from outdoors, so encapsulating your attic may not be an issue (as you know, I’d recommend you test it before, after, and during). Spray foam is not a favorite of mine because of flame retardant offgassing, but if you ventilate properly and don’t spray everywhere in the house you can do it well.
If I am not wrong: Intello for indoors is a vapour layer to prevent vapour diffusion from inside to the outside.
And Zip is also a vapour layer (also as WRB,...) to prevent vapour from outside to go to the inside? However, the Zip board allows passing vapour from the inside to the outside. Am I correct?
Intello is an air barrier that works in both directions. It allows vapor diffusion (drying) when humidity is high. The direction depends on the season.
Do you guys not use strapping for the drywall or are they covered by the intello plus?
No strapping
so if part of the house has holes not putting hole in the rest of the house doesn't improve heat loss? Insulation is like hole less insulation the bigger the hole the more the smaller so not having holes doesnt help? Obviously theres a return on investment concern but that's not the same so if you have multiple points of least resistance you have more heat loss, ,ore heating coosts.
Hi, great video. Can you tell me the software program you are using to calculate the insulation values?
I am also trying to design the insulation values for our new build next year to help determine what levels are best.
Looks like Rem Rate.
Great video. Quick question, what happens when the vapour hits the radiant barrier on the underside of the roof?
Won’t happen- since the airsealing details are in place you’d need pure vapor diffusion, which just doesn’t move enough moisture to do anything. Airsealing is the way to stop condensation anywhere but Alaska.
Home Performance ah ok, so the intello would never let through so much vapour that it would cause condensation. Makes sense
Does rockwool under a slab get squished and lose some of the r-value?
No, the 110 panels have very high compressive strength
"I rock So hard" 😂😂😂
Genuine question. How can something be air tight but allow water vapor to move through? An h2o molecule is larger than nitrogen or oxygen right?
EXCELLENT QUESTION! Too much to type, so here is your answer:
th-cam.com/video/oc_ITq5y9qA/w-d-xo.html
Ever had a gortex jacket
Breathable yet waterproof
@@alexcampbell5371 gortex stops liquid water not water vapor though right. I have never had one so I wouldn't know
Michael Murphy if you wear a plastic poncho in the rain you will still get wet if you are covered in a gortex fabric you will stay dry as it allows air and vapor to pass through were as plastic traps humidity....
at least that’s my story and I have used gortex and plastic ponchos many times
The intello is permeable to water vapor and nitrogen and oxygen but it diffuses slowly thus it is still considered air tight. I think.
My wife and I are about to embark on gutting an existing 70s 2-story house, and "remodeling" into a single story home office/gym which will be well sealed and insulated. At about the same time we're building a small, near passive house. Your videos have been super informative. Question on the electrical outlets. Seems like a quick couple of shots of an expanding foam sealant would be far easier and quicker than the butyl tape. Did you consider that? Also, is the space above the ceiling rockwool vented?
Foam cracks snd degrades differently than this tape over the years- we aim for this to be a 100-year house. And the ceiling cavity is not vented, no need. No moisture will accumulate there, because of the interior wrap and all layers vapor permeable, plus in Atlanta the temps are fairly mild.
And there is now no relationship between the inside and the outside at Corbett’s house.
It’s a good thing you have a Mitsubishi system at your place because you’re gonna be wanting that low ambient cooling at thanksgiving!
Wait... Am I a control freak? Is this what I’ve become?
I think it better analogy would be a mechanics working on your car and after it's all fixed continues to put on a turbo, exhaust, cam etc...... Lol
Please provide information on electrical box tape.
Http://FourSevenFive.com
Check out Extoseal Encors
@@HomePerformance Thank You! Enjoy all of your videos.
What energy modeling software do you use, and is it something that a homeowner could afford?
REM/Design. Afford money wise, sure, $500- time investment to really master it, probably unrealistic.
So I am a bit confused. If you already have a continuous air barrier on the exterior, why put this Intello on the inside of the wall? I know it is a "smart" vapor barrier, but it seems like you are just creating another obstacle for any moisture that might get in the wall from drying to the inside. Plus, the drywall itself is somewhat of an air barrier, which means you will now have three different air barriers, which just seems unnecessary. Is there some benefit to this that I'm missing?
It's a barrier for air, not moisture. The main reason here would be that there is a vapor impermeable radiant barrier blocking drying if any moisture gets into that area above the rockwool. So you really don't want moisture there at all and drywall + Intello gives you a good probability the whole house won't fail.
Is there any way you can specify your wall detail on the shed style roof where the two walls meet at the top. Im wandering how the walls meet with one being straight and the other wall being sloped. Did you put a angle cut on the top of the sloped wall where it will meet the top of the other wall which would be the top corners or is it cut square where it would leave a small gap between the walls.
You angle cut the roof rafters where they rest on the lower wall. It’s in the roof framing vid- search roof on our channel, you’ll see exactly how we did it
@@HomePerformance Oh ok. Cool I missed that video. Will have to check it out. Thats what I was thinking how it was done was to angle cut the framing where the two walls meet. Thanks again. Enjoy the videos.
Thanks Ghetto buddy
Why would you use a fiberous insulation beneath the slab? It will lose R value when wet, which it will be. Also, seems it could breakdown over time due to biologics and dampness, whic ridgid foam will not.
It will not be wet, we have a gravel field beneath with drainage.
What’s your CFM50 and sq footage?
309 and 3000
Question concerning your comment at time stamp 13.30. You mention that the electrical code states that outlet in exterior walls need to be every 6'.
Is that a local electrical code?
National Electric Code 210.52(A) states "A receptacle outlet must be installed in every kitchen, family room, dining room, living room, sunroom, parlor, library, den, bedroom, recreation room, and similar room or areaso that no point along the wall space is more than 6 feet, measured horizontally along the floor line, from a receptacle outlet."
This means that outlets can be installed no more than 12' apart ... The 2 outlets are no more than 6' from any point that exists between them.
I must have meant 6' from every entry and then 12' apart. Either way, the exterior walls are an issue to be addressed.
@@HomePerformance Thanks for clarifying. I'm always curious as some states/cities have code restrictions that are greater than the national code.
You gave really good explanations concerning different wall insulation levels. That software package is a great way to help keep a project on budget.
Thanks @TechSkills, appreciate your thoughts.
Hi Corbett, could you tell me if your skillion roof is vented or unvented, building a house with a skillion roof this summer, in northern Quebec, Canada, and wanted to do an unvented with Intello plus and Roxul but was thinking of filling the cavity btw the i-joist...? Would really like a side cut of a good set-up thx!!
Unvented, 5” gap on top. Would NOT recommend for your climate, Dan, you’re dealing with very different temps up there. Filling the cavity sounds good. If you’re nervous you can use Lstiburek’s vapor port detail as well.
@@HomePerformance Thx! So i would go unvented with Rockwool completely filling cavity to top, and Intello plus inside, would you still use a osb with barrier in my case? Appreciate your feedback!
I’d use ZIP on the roof if I were you, actually, unless you’re doing an exterior membrane
What's up Corbett? In NC, so far planning to fill my roof cavity with blown in cellulose and intello, 14in cavity. Had zip scheduled to go up on the deck but been toying with the idea of a Adhesive skin and plywood to allow the I joist cavity to dry to the exterior and rain screen under my standing seam. Any opposition?
I think that sounds great
What software do you use for energy modeling?
I’ve always used REM/Design, but I wish I used Energy Gauge instead
@@HomePerformance I use energy gauge on a very limited basis just for code-required energy calcs. What advantage does it have over REM/Design?
It also is Manual J compliant, which REM is not
👍🏻👍🏻👍🏻
✊🏽
We typically insulate a 2x6 wall with a 5.5" batt in order to prevent it from sagging in the cavity over time.
Not a worry with Rockwool
Do you know anyone who does performance remodeling in CT?
I used to have a top notch guy for you- John Poole with Birmingham Point. Sadly, he may not still be with us, he was in hospice last I heard.
For residential? There a ton of BPI certified home energy firms. There are high-performance builders like Wolfworks. For commercial Steven Winter & Associates?
Detailing god knows how many electrical boxes one by one begs for a wall system design that puts the boxes inside of the vapor retarding layer.
6:52 not true heat rises meaning you need more in the attic than in the walls
Heat does not rise. Hot air rises, when it’s surrounded by colder air.
Actually its 5 inches solid when wrap insulation outside. Comfort board 110 5 inches thick r 20 over cmu block with vermiculite cores. Air gap r 2 and masonry veneer. Canadians usually vapor barrier inside of house. Not only do they tighten head bolts twice but also put and a certain angle extra of tightening. We use low perm wraps to keep moisture flowing out. Yes it does make sense to insulate at different levels. Too much insulation will trap condensation. Or like people spray foaming rim joist pockets creating moisture pockets. Or people trying to use fiberglass around doors and windows. The term we use is educated idiots. Looks good on paper but real world moisture problems happen. Moisture in air tight houses should be addressed. Kitchens, bathrooms, rim joist pockets, basements, and around windows and doors.
At 10:00 where you explain how overstuffing walls yeilds little improvement in performance. Your example is confusing to me because you seem to be saying that its not worthwhile to have great variation in wall performance in a simgle building but your example seems to show that stuffng more insulation than can fit into the wall cavity will yeild little improvement in home performance. I dont think anyone who understands the basics of how insulation works would overstuff wall cavities with the belief that the more product you stuff in there the more insulated the wall would be. What we really want to know is how detrimental is it to have a wall,/door/ceiling that's less insulated im an otherwise highly insulated house? Not every house is a new build and some insulation improvements like 1" exterior foam are low hanging fruit while others such as triple pane windows are much costlier.
If you have continuous external insulation there may not be a noticeable difference. Otherwise for insulation more is better and enough is enough.
Terrible analogy about the mechanic retightening thing once it’s been tightened…….. not a thing
I am close to building in the ATL area soon. From your energy analysis, would this also indicate that there is no real advantage to going from an R15 2x4 wall to an R23 2x6 wall? For some reason I thought I had seen an analysis that showed you are on the "flat" part of the curve at this point. I plan to install an ERV system to complement what is hopefully an airtight house using Zip and AeroBarrier.
You don’t need AeroBarrier if you’re using ZIP, Neil. Good plan though- let me know if you want any help locally!
@@HomePerformance and thanks for that. Just trying to balance the cost/benefit of Zip, ZipR, aerobarrier, traditional HVAC versus VRF, solar, etc....
Lots of ways to get stuck in the weeds for sure!
@@jneilcopeland are you in a hot humid climate?
Two things.
1. I'm not a big fan of zip sheathing. It's osb and you should read what building science corp has to say about osb - not good and plywood is much better.
But did you know you many not even need sheathing? If you are using stucco you can use it without sheathing-no osb to rot away or get mouldy and it saves money too
2. In a hot humid climate vfr is generally not a good idea. It can and will reduce the flow low enough that the coil is not colder than the dew point.ie it maintains temp with no dehumidification which is a bad idea. If some one tells you to get a dehu they should also tell you that a dehu can consume up to 10kwh a day, which could be up to 1/3 of your energy consumption
@@jl9678 Yes, I will be building in Atlanta. I live in a 20 YO house that I consider very drafty and desire to have a tight home going forward. What would you recommend as an alternative to Zip, OSB, and stucco (which wont work for the aesthetics of my home).
I fundamentally disagree with your approach to remove plastic from your home + allowing any moisture to travel into your wall. I will however admit that most of everything else you say is spot on.. Perhaps the difference is I'm in a much farther north climate. So it might be climate differences. Code won't even allow semi-permeable membranes (like Intello) here.
Right on- I always try to include the exemption ‘unless you’re in Alaska or Miami’ to that plastic bit. Anywhere there is more than one season, plastic is in the wrong place in the assembly half the time.
Airplane
No
“Just trying to make all the women in my life happy” BETA mistake.
I try not to take advice on women from Cynical Dads in Texas
@@HomePerformance
Mistake #2
LMAO
@@HomePerformance
Love the vids bud. 👍🏻
Lots of good info.
See? You’re not cynical at all- just funny. Thanks fellow dad.
You want your sleeping spaces to be cooler than your living though. Especially with women. Just saying my frustration when she turns it down to 60 at night then opens a window to heat it back up is immeasurable.
All women are different, Steven, and to add to your problems so are the men- the real goal here is control.
@@HomePerformance Right but for both genders you want your sleeping space cooler than your living. Just been my experience if favors one, didn't mean to imply uniformity.
I hear you Steven, don’t worry- but I’ll also point out that most people have never experienced a truly high performance home, and the feelings of comfort and the taste of fresh air do not require bumping tstats up or down or opening windows.
Very annoying presenter
Well poo on you too