Steve, very refreshing. I see very few builders who give this any thought at all. On pitched roofs I often specify a warm pitch roof so that there is a gap above plasterboard on vaulted ceilings. Trouble is builders seem not to have any experience and immediately change the design to between and under insulation and the problem is back. This is kind of basically the same as your drop ceiling idea we need to convince more builders to go warm roof construction.
@@muso31 Novia 1200 from a very quick glance looks ideal. If in any doubt the best thing to do is to pick up the phone to the manufacturers and explain your build up and ask what they would specify.
Have just watched about 10 of your videos trying to find a suitable solution for downlighters in my old kitchen extension flat room. Looks like dropping the ceiling is best. Thanks for all your work.
To be honest, if you’re doing a loft conversion with 150mm roof joists. You’ll need 120mm insulation between the joists, then 25mm battens on top of your roof joists for cross ventilation and to achieve 50mm air gap. If you add 75mm underneath for your downlights, you may aswell lose the battens and do a warm deck.
Great video and one I could have done with seeing 2 years ago as I looked everywhere for a solution to the problems you quite rightly outline for my garden room with a hybrid roof. In the end I made wooden frames in between the joists for each downlighter, inserted a sealed VCL unit (parcel shaped with bottom open with flaps to fix to frame), then went over the whole sealing with VPL (butyl tape over where it spans the VCL box giving a double seal). Then drilled though ceiling and into the boxes and inserted shallowest downlighters I could find. Boxes are quite big (450x450) so some airflow round the downlights. Not perfect or pretty (not that you can see them), but better than just drilling straight through the VCL and creating a chimney behind every downlighter. I'm just a DIYer, and if I can think about this issue and find some sort of solution, not sure why professionals can't. I'll send you some pictures if you have an email address?
👍 Thanks, this has given me something to think about. I have Saxby Orbital Plus LED units to install, along with the 95mm Thermahoods, prior to reinsulating the loft. The lighting manufacturer states only the following: "Ensure that the void depth is a minimum of 75mm" and "This product is suitable for covering with insulation 270mm". I've asked the manufacturers about your concerns about the heat build-up and airtightness and will wait to hear back...
I did this method of cutting my own recess into the PIR and taping inside the recess. Yes it took a long time. Self build so wasn't so critical. Flexi taped around the cables to seal. 50mm air gap above the PIR. Sparks could not fit the lights and drivers in (even though I gave them the cutout dimensions in writing), so had to find different lights. Found some led panel disc lights that were barely thicker than the plasterboard and they fitted in fine. Tested with room heated to 20c. 0c outside and frost on top of the rubber roof. OSB deck is cold and dry. I can get my hand up the rear soffit vents and all feels dry and cold above the PIR.
Interesting video Steve. Currently insulating and plasterboarding a flat cold style roof for a lobby measuring 2m x 3m linking a house with a garage which has low headroom about 2.2m. I was going to go for spots but don't fancy breaching the 100mm deep PIR insulation and vapour control layer beneath it with installing spots. There are many slim circular bulkhead lights on the market now with tube fittings, some as low as 30mm in depth from ceiling level which dont require chopping holes in the insulation or vapour control layer. all it requires is a 5mm wide x 3mm flex which is much more sealable. By the time you've battened the ceiling down to take account of the spots so as not to breach the VCL and insulation above, it just aint worth the hassle and expense installing them in a cold roof.
Like most things it's all about cost if you're doing it yourself it's also time and also knowledge a lot of people just don't know or understand are used to be one of those
I accidentally deleted my comment editing it so I'll post it again. Just dont fit them. As a spark I have fitted many and they hammer the integrity of the insulation, vapour barrier and the air flow gap can be compromised by the insulation getting shoved upwards with sparks sometimes not pulling the insulation back down if it moved. It's not worth it. Panel led lights are much shallower and other good alternatives exist. Spend thousands and install a flat roof with great attention to the insulation and vapour barrier then smash the hell out of it to recess some lights. Plain stupid.
Best not fit them. Many alternatives out there. Surface mounted slimline alternatives. In most loft dormers I have put on 4 wall lights and left the ceiling intact. I tend to use 7x3 treated timber. Cross batten with 3x2s. staple alluminium vapour to the top and then OSB. The put 75 mm between the joists. 50mm on top, tape, vapour and board. Never had any problems. Always have a pitch on the roof as heat rises to the highest point. Longevity of the roof is increased and ventilation improved due to the gradient. If it's a big dormer and not sighted. A few mushrooms at the highest points.
I found downlighters which are only 23mm deep, in 12.5mm plaster board only 10mm of the fitting protrudes trough. The driver is 22mm high. So a drop ceiling made on 44x44mm timbers would be sufficient, then there is still 22mm above the drivers and 34mm above the light fittings to provide ample circulation and prevent overheating of the vapour barrier. The timbers for the drop ceiling are fitted at a 90 degree angle to the roof joists and some cutouts were made in the top of these timbers, so ample air circulation is possible between the vapour barrier and plaster board. But now as a warm roof is going to be installed in this place the vapour barrier and insulation on the inside are going to be removed, as the ventilation under the roof from the outside is going to be closed off. So the fitting of any type of light fittings, ventilation ducts etc. are not causing any issues anymore.
Had the exact same thoughts with my warm roof build on my conservatory - so I changed my plan and went with some nice pendant lights, luckily I had plenty of height.
What a great video! I'm in the position where I'm about to try and install D/L's in my extension and was wondering the exact same thing. This has confirmed what I was initially worried about. Might need to ditch them all together or see what might be now out on the market. Thanks Steve.
Well done Steve. I agree with other comments. Don’t do it. The shallow lights work, but you just need to route the cables and install the drivers in an accessible location which could be anywhere. They don’t need to go right next to the light unit. In an ideal world, a drop ceiling would be great, but most loft conversions have limited head height to start with, so loosing 75mm is not really option. Well done for setting this up and showing us all. 👍
Homeowners are keen on recessed spots, but it just seems to be best to stick to pendants to avoid all the variables of trades involved. If there's enough head height, go for the drop ceiling, may be even dropped ceiling light box so it's not over the entire ceiling (and can have it's own ventilation) - make it into a decorative element? I guess the good thing is this only applies to loft conversions and extensions, though the former can suffer from head height restrictions by default. Great videos Steve.
local garden center buy 99p clay flower pots put them over the holes and put the insulation around them job done. only led down lights mind but they create a thermal barrier and heat sink then you can cover the pot in what ever you want used this trick for years never had a problem cheap and simple.
Another good video. When we do our extensions its always a drop ceiling and cavity walls behind our plasterboard. There aren’t many out there that will notice the height of a ceiling. Though saying that a lot of our recent projects have been asking for a 2.5m ceiling height. So dropping it to the light manufacturers specs is not noticeable.
@@SteveRoofer we’re up in sunny Scotland covering the central belt. We put a dropped ceiling in our last extension and sunroom we completed in Perthshire and a dropped ceiling in the the renovation we carried out over in Lewis. That includes ceilings where it’s a pendant light. When installing down lights we’ll use a super slim. But we’re keen on insulation. So all our services run behind 15mm plasterboard walls but in front of PIR insulation so why not carry that on in the ceiling is the way we see it. We know then no matter what’s being installed it shouldn’t harm the VCL.
It would take a very patient and conscientious contractor to do this correctly, with amazing co-operation between sparks and plasterer, also it would be impossible for anyone to check the finished job to certify it's been done right. A warm roof design gets round all these problems as well as venting issues.
Dropping the ceiling by 75mm and installing to create a clearance sound fine and dandy, but my question being is wouldn’t the heat of the light cause moisture on the vol as there is no ventilation as the ventilation is in the upper portion of the roof. Love ya videos mate. Keep them coming.
As an electrician I'd also be thinking about how you would replace the fittings without cutting the ceiling, because LEDs do fail and usually the whole fitting (not just the bulb) needs to be replaced. Ideally there needs to be a decent size void and any divers/transformers/terminal blocks need to fit through the ceiling cutout. With some slack on the cable the whole lot can then be pulled out, with the connections re-made with it all hanging out, and then all fitted back through the hole. I'd say if there's enough headroom, then drop ceiling all the way, which also means your cables don't need to penetrate the vapor barrier. Lower ceilings do also reduce heating costs albeit I'm sure many clients want taller ceilings for aesthetics.
Maybe we want to be thinking about low-profile lights that are rated for direct contact with the bottom of the insulation and don't need any recess carved, and also, running DC over the wires to them from a central transformer box located outside the ceiling stack to avoid hot electronics doing the power conversion at each light.
Hi Steve, I was hoping for some advice on the following scenario. I am trying to smooth off the ceiling for my upstairs bathroom, which currently has a stipple artex finish painted with moisture resistant bathroom paint. I also hope to fit down lights in the ceiling. I am reluctant to scrape off the artex due to the risk of asbestos. It has been recommended I overboard it with vapour check plaster board. The issue with this is I have coving around the edge of the ceiling. My two options are: 1) overboard directly on top of the existing ceiling and f8nd a way to smooth over the step between the overboard and coving. This would allow the back of the downloghts to extend into the loft. 2) Fit battens to lower the overboard enough so the coving would be covered up (my ceilings are high enough to allow this). My concerns are with both scenarios, I would get moisture trapped in the void between the overboard and the ceiling leading to rot as there wouldn't be any airflow, especially as the bathroom is a high moisture area. Any advice or alternative solutions would be greatly appreciated. Thank you.
As a builder myself, i don't think it should be down to the builder to contact manufacturers etc; i think the responsibility for products used should be on architects/s engineers/building control/etc and it would be down to the builder to ensure correct installation; wont happen though
Surely PIR foam sheets are closed cell foam which is vapour proof, so why would you need a vapour barrier in the divot. Why can’t you just seal the vapour barrier to the foil around the hole?
A common extension is the flat roofed rear extension kitchen with roof lantern, often with no thought about the airflow, plus about 18 of these spotlights. Always wondered how they perform!
Aren't they normally warm decks extensions usually have the height to have a warm deck the problem is usually lofts where head height is limited which is why a cold deck is often specified
Good stuff and thought provoking. It would seem that warm roof or dropped ceiling are the only practical alternatives - if you are wedded to downlights.
@@SteveRoofer not sure if you will see this as your reply at @normanboyes4983 was over a year ago, but do you have any videos/examples of your multi-foil option that you refer to? thanks, great info always in your video. Sean from dingle, ireland
Thanks Steve at last people are getting it thanks to people like you, at building control we have been asking for more emphasis on builders to keep the insulation U value and the vcl in tact for sometime. I agree there's not a perfect solution out there yet if you want recessed downlghters fitted.
I don't speak from experience but recently found a plaster-in led strip track that not only looks great but allows the driver to be sited within a wall panel or similar. Perhaps thats the way to go. It does however mean a double skin of plasterboard though
I've been getting really confused with all the barriers, which order, air gaps etc but these have helped better than most all others combined... shame they only came up after hours of others. The cold roof explained is what I really needed. One thing I don't get is the real difference between a vapour varrier and dpm if the goal is stop moisture from inside penetrate the insuoation and condense inside it then if dpm stops more then aren't they always better?... or is the vapour barrier the outside where air gap is and if so is it really needed if its vented?
With cold flat roofs u should design under the joists as well as over. Counter batten below the joist is way to go. Also have the lighting circuit designed so all the Jb’s/drivers/remote receivers etc are all in one hub in a cupboard below the ceiling somewhere so they have air/space to stay cool and so faulty item can easily be replaced. The use the counter batten for all the cables runs. I would also accept the limitations. Don’t have downlights if it means you have to cut the vapour barrier/insulation. The slim like light look nice, LED strips are getting popular now where u plaster the channel into the ceiling.
We are having a flat roof extension in timber form. Is a warm roof the best option for wiring and spots. Is there a need for insulation between the joists? Also what thickness should the pir on the roof be? Great videos Steve, learning so much, thank you
Yes warm roof is the way to go and no you don't have to have insulation between the joists although you can have some if it's not that much about one third
You can't fit the spotlights into the insulated plasterboard you would have to put the insulation under the joists then space Down the plasterboard and then fix the lights
Hi Steve. What are your thoughts on Kingspan roofing panels for a garden office. Would they suffer from interstitial problems? How would you suggest fitting lighting directly to the panels? I am embarking on a garden room build in the spring in line with permitted development and want to ensure I get the roof right. Many thanks for the videos as guidance to assist in my decision process.
they could operate much like SIPS in terms of interstitial condensate (IC) - I think the SIPS manufacturers expect the SIPS to have IC but they state that it dries out in summer months. Is your garden room 'low occupancy'? Permitted development with the 2.5m height restriction and high occupancy usage don't mix too well - compromises are inevitable unfortunately.
@@molydood yep intended to be low occupancy. I am seeing a lot of people screwing batons for plasterboarding and lighting systems into the panels. Will all these screws essentially become thermal bridges and lower the insulation properties of the panels?
@@danielnorton9363 if low occupancy then I would personally feel comfortable with the Kingspan panels, but it's impossible to know for sure what will happen, as with all these things. I would expect the screws to attach the batons to the panels to be only just long enough to penetrate the metal skin on the panel, as the internal PIR wouldn't provide much or any of a fix, so presumably its all held in place with techfast type screws straight into metal? If that is the case then I can't imagine the screws affecting the thermal properties very much. You don't have any timber joists every 400 or 600 so already you have taken one quite large thermal bridge out of the equation so I reckon this would still perform really well thermally vs traditional roof build up
I'm having this problem. I'm converting a detached garage at the bottom.of my garden into a recording studio. If he to extend the joists down so I can get a 50 mil gap and drill holes at the top to allow airflow. I can't come down anymore as i will be scraping my head on the ceiling. And I'm also not sure if it's going to be sound proofed enough because I can't sacrifice anymore on on ceiling height.
It's just another reason why warm roofs are far superior. This is a non issue for those. I understand not everyone can have warm roofs. Height constraints etc. But if I was having a cold roof, I wouldn't even entertain the idea of down lights.
@@aasiya7016 I'm guessing that you can probably trust that most are doing their best and doing what they think is right, whilst the customer insists on the sleekest light fittings. As Steve's videos show, it's quite a complicated thing to get right.
Very informative👍 could you advise please just had my flat roof ceiling pulled down along with damp fibre insulation which was 20 yrs old as we had water ingress - sorted now - we would like mineral wool back as insulation, do we need vapour barrier as its a cold roof and if so how do we make that airtight (not sure if walls are airtight as building regs have changed a lot in 20 years)thanks for the tip about the centre light fitting
Quick question for you, when you put the downlight into a drop ceiling isn't there a problem with condensation forming on the vapour barrier and then dripping down into the plasterboard?
If a roof is flat a vapour barrier is more effective than roofs that are pitched ? and would light fittings be less of a roofing problem on a pitched roof?
In a lot of lofts I've been fitting a triso insulation coupled with a pir behind. I cross batten with 25mm. I've always wondered if there's a downlighter that's shallow enough to sit into that gap. Untill I find something I don't recommend them being installed. Not worth the risk
@@SteveRoofer yes mate I love the stuff. Been using for years now without any issues. Less mess and less wasteage than pir board. I'll fit it all then my electricians can first fix around the battens thus keeping it totally air tight, it's a great system
I have exactly thus question we have a low pitch dormer being extended which requires spots so head room for drop is not there, room too large for wall lights so a cut out is only option
I have had a garden room built and I know they would have just cut holes in the plasterboard and VB to install them. If there is adequate roof ventilation and the room is only used for a couple of hours a day is that good enough? Obviously old houses didn’t have VBs but many are fine and this has to be down to less insulation and better ventilation Any help would be much appreciated before I rip it down and cry ha
Great video. Would it be possible if for instance you have excess room, to push the insulation higher up in to the joist (still with 50mm air gap). To allow space for fittings underneath?
I have a 175mm joist, will be battening above to allow air flow from the pitched sides of the roof to go over the steel beams and through the flat roof section). Will be using 120mm boards.. so I have some room to play with in regards to the ‘positioning’ of the boards. Hope that makes sense?
I'm planning for a Garden Room build for a home gym upgrade (Approx 5m x 8m). I'm planning on have a Flat Cold roof with Solar panels on top. Being a gym, my concern is condensation build up in the gym due to sweat etc. I originally intended to install some kind of extractor fan for ventilation, how can i do this without affecting the vapour barrier?
Hi Steve, I am having a garden room built and I’ve followed all the flat roof videos and chosen to go for a warm deck roof. Your advice has led me to making some choices regarding materials and the final piece of the jigsaw is the impact of adding a log burner with the the chimney conundrum. Out through the wall or out through the newly constructed flat roof? If you’ve any advice tucked away can you please signpost me? This video was great as I noted that on the comments, fitting down lights in a warm Dee kitchen does not have the same issues. Thanks for all you do to pass on great advice. Regards, Wayne
@@SteveRoofer Many thanks Steve. I really have specifically identified the materials and process I want my contractor to follow. The flat roof joins the existing tile roof 3/4 rows up so now looking for how that is done. Learnt so much from your presentations and knocked up models. Brilliant! Wayne
can you seal the light fittings in or will the air still track through from around it because the vapor barrier has been breached, ive done a lot of loft conversion's with low headroom and the vb breach has always been a problem, maybe led tape is the future in these situations
If the light fitting is to be installed in a sealed hood then why not make the light fitting NOT! fit air tight and in fact have an air circulation design around it? (Built into the unit itself) Basically, the first 2 to 3 mm of the round surface that makes contact with the plaster would be stood off with some kind of grill design? (yes it would require maintenance as in dusting/hoovering to keep the grill clear)
Thanks for sending over the link I've watched many of these men's videos yes there are allsorts of new lights out there and the new LEDs are definitely making a difference some of them as you quite rightly say have all the electronics building
@@SteveRoofer Do you think having a warm roof ie insulation just positioned under the roof is a better option ? Cuts out all concerns about moisture leaking in from the living space below .
Steve, very refreshing. I see very few builders who give this any thought at all. On pitched roofs I often specify a warm pitch roof so that there is a gap above plasterboard on vaulted ceilings. Trouble is builders seem not to have any experience and immediately change the design to between and under insulation and the problem is back. This is kind of basically the same as your drop ceiling idea we need to convince more builders to go warm roof construction.
I agree
On a warm pitched roof would you add a VCL behind the ceiling plasterboard? Or is the VCL on the bottom deck under the insulation adequate?
@@muso31 VCL immediately behind plasterboard, with the intention that it stops ingress of warm moisture laden air into the roof construction build up.
@@DDGXMUSIC would you use something like novia 1200 for this still? Or a smaller gauge as it's less important in a warm roof?
@@muso31 Novia 1200 from a very quick glance looks ideal. If in any doubt the best thing to do is to pick up the phone to the manufacturers and explain your build up and ask what they would specify.
Have just watched about 10 of your videos trying to find a suitable solution for downlighters in my old kitchen extension flat room. Looks like dropping the ceiling is best. Thanks for all your work.
Play, the video was helpful
To be honest, if you’re doing a loft conversion with 150mm roof joists. You’ll need 120mm insulation between the joists, then 25mm battens on top of your roof joists for cross ventilation and to achieve 50mm air gap. If you add 75mm underneath for your downlights, you may aswell lose the battens and do a warm deck.
Excellent reply that you
Great video and one I could have done with seeing 2 years ago as I looked everywhere for a solution to the problems you quite rightly outline for my garden room with a hybrid roof. In the end I made wooden frames in between the joists for each downlighter, inserted a sealed VCL unit (parcel shaped with bottom open with flaps to fix to frame), then went over the whole sealing with VPL (butyl tape over where it spans the VCL box giving a double seal). Then drilled though ceiling and into the boxes and inserted shallowest downlighters I could find. Boxes are quite big (450x450) so some airflow round the downlights. Not perfect or pretty (not that you can see them), but better than just drilling straight through the VCL and creating a chimney behind every downlighter. I'm just a DIYer, and if I can think about this issue and find some sort of solution, not sure why professionals can't. I'll send you some pictures if you have an email address?
DIY,s tend to take time and do a better job
👍 Thanks, this has given me something to think about. I have Saxby Orbital Plus LED units to install, along with the 95mm Thermahoods, prior to reinsulating the loft. The lighting manufacturer states only the following: "Ensure that the void depth is a minimum of 75mm" and "This product is suitable for covering with insulation 270mm". I've asked the manufacturers about your concerns about the heat build-up and airtightness and will wait to hear back...
Please get back to me with that they say
We would all like to. Know what they said
They didn't get back... I don't think it was something they had the need to test for.
I did this method of cutting my own recess into the PIR and taping inside the recess. Yes it took a long time. Self build so wasn't so critical. Flexi taped around the cables to seal. 50mm air gap above the PIR. Sparks could not fit the lights and drivers in (even though I gave them the cutout dimensions in writing), so had to find different lights. Found some led panel disc lights that were barely thicker than the plasterboard and they fitted in fine. Tested with room heated to 20c. 0c outside and frost on top of the rubber roof. OSB deck is cold and dry. I can get my hand up the rear soffit vents and all feels dry and cold above the PIR.
Thanks
Interesting video Steve. Currently insulating and plasterboarding a flat cold style roof for a lobby measuring 2m x 3m linking a house with a garage which has low headroom about 2.2m. I was going to go for spots but don't fancy breaching the 100mm deep PIR insulation and vapour control layer beneath it with installing spots. There are many slim circular bulkhead lights on the market now with tube fittings, some as low as 30mm in depth from ceiling level which dont require chopping holes in the insulation or vapour control layer. all it requires is a 5mm wide x 3mm flex which is much more sealable. By the time you've battened the ceiling down to take account of the spots so as not to breach the VCL and insulation above, it just aint worth the hassle and expense installing them in a cold roof.
Like most things it's all about cost if you're doing it yourself it's also time and also knowledge a lot of people just don't know or understand are used to be one of those
I accidentally deleted my comment editing it so I'll post it again.
Just dont fit them. As a spark I have fitted many and they hammer the integrity of the insulation, vapour barrier and the air flow gap can be compromised by the insulation getting shoved upwards with sparks sometimes not pulling the insulation back down if it moved. It's not worth it. Panel led lights are much shallower and other good alternatives exist. Spend thousands and install a flat roof with great attention to the insulation and vapour barrier then smash the hell out of it to recess some lights. Plain stupid.
Excellent thanks for the comment can't agree with you more
Interesting. Could be a solution, but where do you put the transformer?
@@molydood There is no transformer . The led driver is either integrated into the light fitting or gu10 lamp
Best not fit them. Many alternatives out there. Surface mounted slimline alternatives. In most loft dormers I have put on 4 wall lights and left the ceiling intact. I tend to use 7x3 treated timber. Cross batten with 3x2s. staple alluminium vapour to the top and then OSB. The put 75 mm between the joists. 50mm on top, tape, vapour and board. Never had any problems. Always have a pitch on the roof as heat rises to the highest point. Longevity of the roof is increased and ventilation improved due to the gradient. If it's a big dormer and not sighted. A few mushrooms at the highest points.
Sounds like a good robust constitution
This is exactly why I used plaster in profiles and 18 m of continuous led strip, no insulation or barrier was harmed in the process 😉👍
Good idea
Do you have any photos of this bud? I'd rather go down this route instead of spots but not sure how it would look as a replacement
As dalturbo said.. do you have any pictures of this as well as the lights themselves? I'm looking to go down this route as well.
@@jp6975 drop me your emails guys and I’ll send some pics over
@@trashermoto thanks dor the offer trashermoto - appreciated. Seems TH-cam doesn't allow direct contact with other users. Grrrr....
I found downlighters which are only 23mm deep, in 12.5mm plaster board only 10mm of the fitting protrudes trough.
The driver is 22mm high.
So a drop ceiling made on 44x44mm timbers would be sufficient, then there is still 22mm above the drivers and 34mm above the light fittings to provide ample circulation and prevent overheating of the vapour barrier.
The timbers for the drop ceiling are fitted at a 90 degree angle to the roof joists and some cutouts were made in the top of these timbers, so ample air circulation is possible between the vapour barrier and plaster board.
But now as a warm roof is going to be installed in this place the vapour barrier and insulation on the inside are going to be removed, as the ventilation under the roof from the outside is going to be closed off.
So the fitting of any type of light fittings, ventilation ducts etc. are not causing any issues anymore.
Sounds like problem solved
Can you share a link to said downlighers?
Excellent Steve.... problem solving...glad it's not just me questioning everything 👍😬
You and me both!
Had the exact same thoughts with my warm roof build on my conservatory - so I changed my plan and went with some nice pendant lights, luckily I had plenty of height.
You can use downlights with a warm roof
@@SteveRoofer is this because a vapour barrier isn't required in the ceiling void as there's one on the deck?
Tracklights avoid this problem.
What a great video! I'm in the position where I'm about to try and install D/L's in my extension and was wondering the exact same thing. This has confirmed what I was initially worried about. Might need to ditch them all together or see what might be now out on the market. Thanks Steve.
Glad it was helpful!
Well done Steve. I agree with other comments. Don’t do it. The shallow lights work, but you just need to route the cables and install the drivers in an accessible location which could be anywhere. They don’t need to go right next to the light unit. In an ideal world, a drop ceiling would be great, but most loft conversions have limited head height to start with, so loosing 75mm is not really option. Well done for setting this up and showing us all. 👍
Thanks
Homeowners are keen on recessed spots, but it just seems to be best to stick to pendants to avoid all the variables of trades involved. If there's enough head height, go for the drop ceiling, may be even dropped ceiling light box so it's not over the entire ceiling (and can have it's own ventilation) - make it into a decorative element? I guess the good thing is this only applies to loft conversions and extensions, though the former can suffer from head height restrictions by default. Great videos Steve.
Wall lights re the way to go
@@SteveRoofer Great option.
local garden center buy 99p clay flower pots put them over the holes and put the insulation around them job done. only led down lights mind but they create a thermal barrier and heat sink then you can cover the pot in what ever you want used this trick for years never had a problem cheap and simple.
Second person to mention this and its a very good idea
isn't clay porous though and hence not solving the moisture movement problem?
Another good video. When we do our extensions its always a drop ceiling and cavity walls behind our plasterboard. There aren’t many out there that will notice the height of a ceiling. Though saying that a lot of our recent projects have been asking for a 2.5m ceiling height. So dropping it to the light manufacturers specs is not noticeable.
Thanks don't know where you are in the Uk but i never see dropped ceiling in domestic flat roofs
@@SteveRoofer we’re up in sunny Scotland covering the central belt. We put a dropped ceiling in our last extension and sunroom we completed in Perthshire and a dropped ceiling in the the renovation we carried out over in Lewis. That includes ceilings where it’s a pendant light. When installing down lights we’ll use a super slim. But we’re keen on insulation. So all our services run behind 15mm plasterboard walls but in front of PIR insulation so why not carry that on in the ceiling is the way we see it. We know then no matter what’s being installed it shouldn’t harm the VCL.
Many Thanks - Excellent Video - How do you batten onto vapour barrier without compromising it?
It would take a very patient and conscientious contractor to do this correctly, with amazing co-operation between sparks and plasterer, also it would be impossible for anyone to check the finished job to certify it's been done right. A warm roof design gets round all these problems as well as venting issues.
Exactly my point
Those slim fit downlights still require 40mm clearance above and 50mm clearance around the edges. Also they are not fire-rated so may not be suitable
Yes alway refer to fitting instructions
Dropping the ceiling by 75mm and installing to create a clearance sound fine and dandy, but my question being is wouldn’t the heat of the light cause moisture on the vol as there is no ventilation as the ventilation is in the upper portion of the roof. Love ya videos mate. Keep them coming.
no because there is nothing there that's cold to condense on
As an electrician I'd also be thinking about how you would replace the fittings without cutting the ceiling, because LEDs do fail and usually the whole fitting (not just the bulb) needs to be replaced. Ideally there needs to be a decent size void and any divers/transformers/terminal blocks need to fit through the ceiling cutout. With some slack on the cable the whole lot can then be pulled out, with the connections re-made with it all hanging out, and then all fitted back through the hole. I'd say if there's enough headroom, then drop ceiling all the way, which also means your cables don't need to penetrate the vapor barrier. Lower ceilings do also reduce heating costs albeit I'm sure many clients want taller ceilings for aesthetics.
You are definitely right, that is the way to do it. However it's always high restraints that seem to be used as the reason to do it badly.
Maybe we want to be thinking about low-profile lights that are rated for direct contact with the bottom of the insulation and don't need any recess carved, and also, running DC over the wires to them from a central transformer box located outside the ceiling stack to avoid hot electronics doing the power conversion at each light.
That all sounds good but unfortunately there is nothing like that on the market and it would probably be very expensive
Hi Steve, I was hoping for some advice on the following scenario. I am trying to smooth off the ceiling for my upstairs bathroom, which currently has a stipple artex finish painted with moisture resistant bathroom paint. I also hope to fit down lights in the ceiling. I am reluctant to scrape off the artex due to the risk of asbestos. It has been recommended I overboard it with vapour check plaster board. The issue with this is I have coving around the edge of the ceiling. My two options are:
1) overboard directly on top of the existing ceiling and f8nd a way to smooth over the step between the overboard and coving. This would allow the back of the downloghts to extend into the loft.
2) Fit battens to lower the overboard enough so the coving would be covered up (my ceilings are high enough to allow this).
My concerns are with both scenarios, I would get moisture trapped in the void between the overboard and the ceiling leading to rot as there wouldn't be any airflow, especially as the bathroom is a high moisture area. Any advice or alternative solutions would be greatly appreciated. Thank you.
As a builder myself, i don't think it should be down to the builder to contact manufacturers etc; i think the responsibility for products used should be on architects/s engineers/building control/etc and it would be down to the builder to ensure correct installation; wont happen though
That's right it should never be down to the builder to make the decision the builder should always follow the design drawings
How did you fix the timber you used to drop the ceiling 75mm without compromising the vapour barrier? Did you use an adhesive?
Ill be showing yu how to do that in a week or so as its also tricky and nobody is doing it
don't you just put the butyl tape down underneath the timber and vapour barrier before you fix it? or is it more technical than that?
Surely PIR foam sheets are closed cell foam which is vapour proof, so why would you need a vapour barrier in the divot. Why can’t you just seal the vapour barrier to the foil around the hole?
A common extension is the flat roofed rear extension kitchen with roof lantern, often with no thought about the airflow, plus about 18 of these spotlights. Always wondered how they perform!
Not that well i'm alway looking at problems especially of there is a GRP roof over the top
Aren't they normally warm decks extensions usually have the height to have a warm deck the problem is usually lofts where head height is limited which is why a cold deck is often specified
Good stuff and thought provoking. It would seem that warm roof or dropped ceiling are the only practical alternatives - if you are wedded to downlights.
Yes but using multi foil and different installations you can probably achieve the same and have a cavity to install lights
@@SteveRoofer not sure if you will see this as your reply at @normanboyes4983 was over a year ago, but do you have any videos/examples of your multi-foil option that you refer to? thanks, great info always in your video. Sean from dingle, ireland
You could do a drop around the edge of the room as a feature to hold these downlights.
Yes that kind of thing is very nice
Just what I was after - cheers
Thanks Steve at last people are getting it thanks to people like you, at building control we have been asking for more emphasis on builders to keep the insulation U value and the vcl in tact for sometime. I agree there's not a perfect solution out there yet if you want recessed downlghters fitted.
Thanks
Warm roof is always the best solution IMO
anything else is a compromise
Yes I agree warm roof all day long
I don't speak from experience but recently found a plaster-in led strip track that not only looks great but allows the driver to be sited within a wall panel or similar. Perhaps thats the way to go. It does however mean a double skin of plasterboard though
why do you need a double skin? LED strip is a great idea though
Can you post the details of the product please?
I've been getting really confused with all the barriers, which order, air gaps etc but these have helped better than most all others combined... shame they only came up after hours of others. The cold roof explained is what I really needed.
One thing I don't get is the real difference between a vapour varrier and dpm if the goal is stop moisture from inside penetrate the insuoation and condense inside it then if dpm stops more then aren't they always better?... or is the vapour barrier the outside where air gap is and if so is it really needed if its vented?
This warm roof is a right pain for us sparks
Don't you mean cold roof ?
You may laugh, but I used ceramic flower pots and blocked the hole up with silver tape. They are fire-resistant and absorb a lot of heat.
Novel idea but probably very good
I did the same. Had a real problem with weeds though, which suggested condensation.
With cold flat roofs u should design under the joists as well as over. Counter batten below the joist is way to go. Also have the lighting circuit designed so all the Jb’s/drivers/remote receivers etc are all in one hub in a cupboard below the ceiling somewhere so they have air/space to stay cool and so faulty item can easily be replaced. The use the counter batten for all the cables runs. I would also accept the limitations. Don’t have downlights if it means you have to cut the vapour barrier/insulation. The slim like light look nice, LED strips are getting popular now where u plaster the channel into the ceiling.
Yes LEDs are changing the game
The answer is at 9:20.
We are having a flat roof extension in timber form. Is a warm roof the best option for wiring and spots. Is there a need for insulation between the joists? Also what thickness should the pir on the roof be?
Great videos Steve, learning so much, thank you
Yes warm roof is the way to go and no you don't have to have insulation between the joists although you can have some if it's not that much about one third
Maybe a soft question, if i dropped the ceiling and used insulated plasterboard as well...what would be the impact?
You can't fit the spotlights into the insulated plasterboard you would have to put the insulation under the joists then space Down the plasterboard and then fix the lights
Great detailed vid
Thansks
What is the most effective way to install downlights in a flat roof? Avoiding any potential condensation. Thanks.
OK thanks
Great video, what are your thoughts on multifoil products in this scenario below the joists?
Hi Steve. What are your thoughts on Kingspan roofing panels for a garden office. Would they suffer from interstitial problems? How would you suggest fitting lighting directly to the panels? I am embarking on a garden room build in the spring in line with permitted development and want to ensure I get the roof right.
Many thanks for the videos as guidance to assist in my decision process.
they could operate much like SIPS in terms of interstitial condensate (IC) - I think the SIPS manufacturers expect the SIPS to have IC but they state that it dries out in summer months. Is your garden room 'low occupancy'? Permitted development with the 2.5m height restriction and high occupancy usage don't mix too well - compromises are inevitable unfortunately.
@@molydood yep intended to be low occupancy. I am seeing a lot of people screwing batons for plasterboarding and lighting systems into the panels. Will all these screws essentially become thermal bridges and lower the insulation properties of the panels?
@@danielnorton9363 if low occupancy then I would personally feel comfortable with the Kingspan panels, but it's impossible to know for sure what will happen, as with all these things. I would expect the screws to attach the batons to the panels to be only just long enough to penetrate the metal skin on the panel, as the internal PIR wouldn't provide much or any of a fix, so presumably its all held in place with techfast type screws straight into metal? If that is the case then I can't imagine the screws affecting the thermal properties very much. You don't have any timber joists every 400 or 600 so already you have taken one quite large thermal bridge out of the equation so I reckon this would still perform really well thermally vs traditional roof build up
@@molydood Thanks. Makes sense.
I'm having this problem. I'm converting a detached garage at the bottom.of my garden into a recording studio. If he to extend the joists down so I can get a 50 mil gap and drill holes at the top to allow airflow. I can't come down anymore as i will be scraping my head on the ceiling. And I'm also not sure if it's going to be sound proofed enough because I can't sacrifice anymore on on ceiling height.
This is so great
Hi steve, great video. Does the electrical cable go between the plasterboard and PIR ? Or does it exit the thermahood and get taped up again ?
exit the thermal hood and get taped up again look at there videos they are very good
I am performing this on an equinox warm roof in conservatory
@@petercawthorne5997 please email over some photos would love to see how you get on steveroofer@gmail.com
It's just another reason why warm roofs are far superior. This is a non issue for those. I understand not everyone can have warm roofs. Height constraints etc. But if I was having a cold roof, I wouldn't even entertain the idea of down lights.
wall lights work well
Can you recommend a cheapish camera / boroscope for getting pictures / views up in hidden spaces like those you show here?
I've tried quite a few however I never like the focus and the view I get from them most of the time I'm using my iPhone or I'm using a GoPro 10
LOL Bring back flourescent tubes
Hi Steve, love watching your videos. Please advise where we can find good, trust worthy roofers.
Don't know but if you find any give me there numbers
@@SteveRoofer the search must go on 😂
@@aasiya7016 I'm guessing that you can probably trust that most are doing their best and doing what they think is right, whilst the customer insists on the sleekest light fittings. As Steve's videos show, it's quite a complicated thing to get right.
Very informative👍 could you advise please just had my flat roof ceiling pulled down along with damp fibre insulation which was 20 yrs old as we had water ingress - sorted now - we would like mineral wool back as insulation, do we need vapour barrier as its a cold roof and if so how do we make that airtight (not sure if walls are airtight as building regs have changed a lot in 20 years)thanks for the tip about the centre light fitting
Quick question for you, when you put the downlight into a drop ceiling isn't there a problem with condensation forming on the vapour barrier and then dripping down into the plasterboard?
I'd imagine that since it's below the insulation it's does not condensate since avoids the cold air
If a roof is flat a vapour barrier is more effective than roofs that are pitched ? and would light fittings be less of a roofing problem on a pitched roof?
Its still a problem i will be covering that subject in a video in week or so
Steve, have you looked at Ovia spotlights? They seem to be fairly minimal. Available on ultraleds website.
will have a look
HI Steve how about in a loft with rockwool insulation cheers great video👍👍🍺🍺
use the hoods
It would be interesting to know the approximate percentage of roofs in London that are flat and made with rubber compounds or asphalt ?
There are still a lot of asphalt roofs out there compared to the new rubber roofs
In a lot of lofts I've been fitting a triso insulation coupled with a pir behind. I cross batten with 25mm. I've always wondered if there's a downlighter that's shallow enough to sit into that gap. Untill I find something I don't recommend them being installed. Not worth the risk
triso is a good product if fitted correctly and sound like you know your stuff
@@SteveRoofer yes mate I love the stuff. Been using for years now without any issues. Less mess and less wasteage than pir board. I'll fit it all then my electricians can first fix around the battens thus keeping it totally air tight, it's a great system
Does this still apply to a tiled pitched roof? Which has a lot more air flow as has the breathable membrane & additional gap from the roof battens
I have exactly thus question we have a low pitch dormer being extended which requires spots so head room for drop is not there, room too large for wall lights so a cut out is only option
I have had a garden room built and I know they would have just cut holes in the plasterboard and VB to install them. If there is adequate roof ventilation and the room is only used for a couple of hours a day is that good enough?
Obviously old houses didn’t have VBs but many are fine and this has to be down to less insulation and better ventilation
Any help would be much appreciated before I rip it down and cry ha
Great video. Would it be possible if for instance you have excess room, to push the insulation higher up in to the joist (still with 50mm air gap). To allow space for fittings underneath?
I have a 175mm joist, will be battening above to allow air flow from the pitched sides of the roof to go over the steel beams and through the flat roof section). Will be using 120mm boards.. so I have some room to play with in regards to the ‘positioning’ of the boards. Hope that makes sense?
I'm planning for a Garden Room build for a home gym upgrade (Approx 5m x 8m).
I'm planning on have a Flat Cold roof with Solar panels on top.
Being a gym, my concern is condensation build up in the gym due to sweat etc.
I originally intended to install some kind of extractor fan for ventilation, how can i do this without affecting the vapour barrier?
Hi Steve, I am having a garden room built and I’ve followed all the flat roof videos and chosen to go for a warm deck roof. Your advice has led me to making some choices regarding materials and the final piece of the jigsaw is the impact of adding a log burner with the the chimney conundrum. Out through the wall or out through the newly constructed flat roof? If you’ve any advice tucked away can you please signpost me? This video was great as I noted that on the comments, fitting down lights in a warm Dee kitchen does not have the same issues. Thanks for all you do to pass on great advice.
Regards, Wayne
Penetrating the warm roof should not be a problem re condensation
@@SteveRoofer Many thanks Steve. I really have specifically identified the materials and process I want my contractor to follow. The flat roof joins the existing tile roof 3/4 rows up so now looking for how that is done. Learnt so much from your presentations and knocked up models. Brilliant! Wayne
who'd wanna be a builder these days😩
How do the battens go up on top of the vapour barrier without piercing it ?
They do piercing, but they self seal because there is a sealing tape behind
Yes but with low ceilings people want spotlights
If they plan coretly they can have spotlights
can you seal the light fittings in or will the air still track through from around it because the vapor barrier has been breached, ive done a lot of loft conversion's with low headroom and the vb breach has always been a problem, maybe led tape is the future in these situations
Compared to how much air leaded through the old ones these are fantastic but still not perfect
More likely to see pigs fly than for a roofer or builder go to this sort of trouble for an electrician
Yes that's the problem people just don't install things correctly
If the light fitting is to be installed in a sealed hood then why not make the light fitting NOT! fit air tight and in fact have an air circulation design around it? (Built into the unit itself) Basically, the first 2 to 3 mm of the round surface that makes contact with the plaster would be stood off with some kind of grill design? (yes it would require maintenance as in dusting/hoovering to keep the grill clear)
These slimline fixtures look interesting. The electronics are included so you just need to supply AC to them: th-cam.com/video/fsIFxyOLJXM/w-d-xo.html
Thanks for sending over the link I've watched many of these men's videos yes there are allsorts of new lights out there and the new LEDs are definitely making a difference some of them as you quite rightly say have all the electronics building
Build a few courses of bricks and put a pitch on it ! A flat roof goes against all logic and common sense .
only because people don't give it the fall it needs new membranes last a long time so if converted well not a problem
@@SteveRoofer Do you think having a warm roof ie insulation just positioned under the roof is a better option ? Cuts out all concerns about moisture leaking in from the living space below .