I'm looking at putting asmall 9m x 3m parapet flat roof extension on the back of my house.This video has allayed all the apprehensions I had about this style of roof. Many thanks. True professionals.
I just want to say a massive thank you for taking your time out to edit and put such valuable information together so people can learn free education at its finest - your a good bloke 🙏👍
Hi, very well explained and built. Exactly how we do it and with the festool saw! We do a few minor different things like 50mm sound proofing rockwool below the deck which has been checked and approved by Kingspan for condensation risk. Which increases u value and makes the roof quieter. We also cut a slight recess in the deck so the warm roof fixings can’t be seen when the roofing cover is laid. Also we don’t build with cavity walls. Our preference is porotherm with external wall insulation. Anyways moving on to the faults I have been told with our roof is apparently we should not be using warm roof fixings with GRP roofs. Plus if we do they must go 40mm into the joist does not include deck or ferrings. Not the case with any other roofing cover. Also at the roofing show the 5 big roofing covering manufactures which include Bauder, Sika, Danosa, Icopal and the others all said tissue based insulation for flat roofs only must be used on top over the VCL and then no ply or osb but the roof covering must go directly onto the insulation board. Indicating warm roofs should not use GRP. GRP companies I am sure would not like this. I have a document which is similar from all these companies as to the physics that mean a warm roof can’t have a osb or ply top deck. So I have wondered if a cement board floor could be used. Then recently due to Grenfell you can’t make a warm roof apparently that does not have a fire certificate. So event though all of the manufactures have a very similar or same looking silver and black sticky VCL (like alutrix 600) simular tissue backed insulation. You have to use all these layers made by the same manufacture as the roof covering to comply with current building regulation as they don’t fire test competitor's simular product and hence only way to get the fire certificate is to use all the materials from one manufacture. So this leaves me confused moving forward as doing it that way would remove GRP roofs and increase costs of materials.
Really appreciate the thermal fixing explanation and model. I've used the wafer head screws and you're right, you see them everytime there's a frost and the heat transfers through the screws.
Well there you go, mate. Every time you can see them in the frost that's heat escaping and simultaneously damaging the roof covering! No worries man! How's things anyway?
Superb video gents. Really appreciate you taking the time to explain this in detail. Been following your videos for a while now and I can honestly say you guys do not cut corners, the care and attention to detail is amazing, like your doing the job on your own home. You have helped an avid self builder massively grow in confidence. Thanks and keep up the great work
I am a Brit from Befordshire now living in San Diego USA. I find looking at UK made videos by you and others keep me in touch wuth the motherland. Also I found laying brick walls in gardens released my stress from work, just like Churchill did. Over here bricks are not popular!
@@mrabuilders6723 Its a long story Adam. I am an electronics eng by training. Had a company in Britain specilaizing in RF engingeering. Sold that to retire to San Diego and be with my US girlfriend of many years. She lived in San Diego and I had been coming here since 1994 on business and got to know her. Now a US citizen, but do miss the UK at times. Had relatives who lived in Ironbridge (owned the fish and chip shop) so your program, and accent are nostalgic for me (many visits to the area and going to West Brom football matches with my cousin). I also am impressed with your work standards, explanations, ethics, and content. Keep up the great work, Best Barry
Very nice job. I've seen false parapets before, PIR horizontally flush up to external face (over cav insulation) then timber parapet on top. If I find the detail, happy to share.
Well...it's a bit of a re-edit to give people a better and easier chance to find the information, but we'd appreciate the view if you don't mind! Thank you!
Got any mates that work on the South Coast? I want a cold roof converted to a warm rood and have no idea who to trust. Pretty on the outside doesn't mean the inside has been done well. I can see you care about both.
Also it seems to me that the most important place in the makeup of the roof components for the VCL vapour control layer is for it to be fitted on the underside of the joists. I have specified SIGA Majrex VCL which has a dual surface that copes with moisture in two different ways, avoiding any problems with interstitial condensation on the underside of the OSB under the GRP/EDPM (this is the most common cause of flat roof failures - not punctures)
Hello again, Nicholas. Whatever you do, do not put the vapour barrier under the joists for a warm deck. It's a massive no no. Follow the instructions of this video, don't deviate from them and it'll be the best that it can be.
@@mrabuilders6723 Another thing I use to avoid thermal transfer and potential dew point/interstitial condensation issues is custom steel lintels with thermal break pads and fabricated brackets holding a galvanised angle which carries the outer skin. It is a new way to replace the traditional welded plate.
Great video lads. Exactly what I was looking for. All the details. What’s the expected life span on this ? Doing my extension next month and undecided on what type of finish to do on flat roof
Hello both. 2 questions please. 1) Theres a lot of strand board used on the layers of that roof. Is it a warm roof solely because you need 150 mmm insulation making cold roof impractical. 2) How did you transfer the rafter centres up to the roof 🤔 . Thanks 🙏
The answer to question two is simply just measure off a fixed point then go underneath and see if you can see a screw poking through, if you can't then you've hit the rafter! As for question 1, it's all about the height of the roof and what you can get away with which we will go through hopefully in the next episode.
Happy birthday! Wondering what you think about the theory which says that you ideally shouldn't use a top deck of OSB because it's on the cold side of the roof and more susceptible to condensation and rot. Better to just have the roof covering directly bonded to the insulation. Also heard that foil faced insulation isn't the best thing to use either, because the foil facing acts as a vapor barrier and you only really want one vapour barrier in the system, otherwise you can potentially trap water vapour in the middle of the system. Needs to be hard for water vapour to get in, easy for it to get out.
Thank you, Ewan. I don't really buy into that to be honest but I'd happily be shown and proved wrong, always willing to learn!!! One of the main issues there is how do you fix the insulation down? We all know that it's not the strongest of materials. Also, the only thing holding your roof covering on is the glue between the PIR and the foil or the fabric type stuff. I won't be charging people for that anytime soon!
@@mrabuilders6723 Where I've seen it done they just seem to use the same thermally broken fixings as you did here, the large "washer" on the top should help spread the load a bit. It's not the strongest, but even in this video you guys are walking around on it without much cause for concern. It's really not that different to the stuff you use under a concrete floor.
I may have missed something but have you incorporated a secondary fall in the firrings to ensure the surface water sent down the deck then goes (perpendicular direction) downhill to the outlet?
Hello Nicholas, yes we have and all that is explained in the previous 2 videos to this one. In those videos you'll see the installation of the diminishing battens and the firring strips. Feel free to check them out. Take care.
Thanks for another great video. Just started a warm deck today. I’m always confused with the vapor barrier. So it stops all the condensation from the insulation soaking the deck below but what happens to all the moisture? Does it just stay trapped forever? 😆
Hello Dom, hope you're well, mate. The vapour barrier is to create an air tight seal from the bottom deck upwards. The whole point of it is so the heat within the room below stays there and can't pass through. That's why we screw through into the rafters, it's to try and maintain the integrity of the vapour barrier and not rely on its "self sealing' properties.
Just out of curiosity, the detail for the timber upstand - does it require vcl internally to prevent mositure laden air from entering into the space. If so, how do you achieve it, is it a simple case of adhering to the inner face of block work and underside of deck around the perimeter?
Hello, hope you're well. If I've understood the question properly...no. We want the air that's in the room to do one of two things...stay in it by not passing through the vapour/make up of the warm roof, or go through the wall and up into the insulated cavity where the only place that it can meet the cooler air of the outside is the very top of the parapet which is beyond the perimeter of the room thus not being an issue. Does that make sense?
Hi Adam, at point 10min on the video Rich was talking about the fixings being 161mm overall, but the total depth of the insulation and OSB would be 176mm ?
Hello Kevin. The thermally broken fixings are 100mm and the screws are also 100mm, so over all when it's all clamped down you've got about 190mm. Obviously you can use longer screws providing the heads fit down the shaft of the plastic fixings!
Could you use 18mm OSB instead of 11 mm therefore countersink the plastic thermal fixings hense have a flatter deck for the GRP ? Love to hear your thoughts ?
Hello Glenn. It's not impossible mate, but the heads of the fixings are approx 5mm if not more, definitely not less, and you'll have to go deeper as to have room to fill over them afterwards, so there's not a lot of meat left to confidently fix down to if that makes any sense?
We do this and use 18mm t&g OSB3. We use a countersink and take out approx 4mm. We thought about filling them in after but have not needed to and you can’t see any fixings. Good idea though to fill fixing hole with foam like they do on this video. But have to agree if you try to do that on 11mm boards you wont have much meat left to confidently fix down. Have to say this video they made is the best one I have seen on here
@@mrabuilders6723 I'm not referring to the thermal properties but the many advantages it has as a top covering over and above that provided by fiberglass. I don't have any real issues with the construction from a thermal efficiency perspective.
@@mrabuilders6723 like anything it depends on how well it is carried out. Personally I have seen first hand many bad fiberglass installations and i doubt these will get anywhere near the quoted life expectancy.
I'm looking at putting asmall 9m x 3m parapet flat roof extension on the back of my house.This video has allayed all the apprehensions I had about this style of roof. Many thanks. True professionals.
Thank you, Karma...that's not the first time I've said that! Follow these steps and you won't go wrong. Good luck! Thanks again, take care.
I just want to say a massive thank you for taking your time out to edit and put such valuable information together so people can learn free education at its finest - your a good bloke 🙏👍
Ah that's a nice thing to say, Dean. Thank you very much, mate. Hope you're well.
Hi, very well explained and built. Exactly how we do it and with the festool saw! We do a few minor different things like 50mm sound proofing rockwool below the deck which has been checked and approved by Kingspan for condensation risk. Which increases u value and makes the roof quieter. We also cut a slight recess in the deck so the warm roof fixings can’t be seen when the roofing cover is laid. Also we don’t build with cavity walls. Our preference is porotherm with external wall insulation. Anyways moving on to the faults I have been told with our roof is apparently we should not be using warm roof fixings with GRP roofs. Plus if we do they must go 40mm into the joist does not include deck or ferrings. Not the case with any other roofing cover. Also at the roofing show the 5 big roofing covering manufactures which include Bauder, Sika, Danosa, Icopal and the others all said tissue based insulation for flat roofs only must be used on top over the VCL and then no ply or osb but the roof covering must go directly onto the insulation board. Indicating warm roofs should not use GRP. GRP companies I am sure would not like this. I have a document which is similar from all these companies as to the physics that mean a warm roof can’t have a osb or ply top deck. So I have wondered if a cement board floor could be used. Then recently due to Grenfell you can’t make a warm roof apparently that does not have a fire certificate. So event though all of the manufactures have a very similar or same looking silver and black sticky VCL (like alutrix 600) simular tissue backed insulation. You have to use all these layers made by the same manufacture as the roof covering to comply with current building regulation as they don’t fire test competitor's simular product and hence only way to get the fire certificate is to use all the materials from one manufacture. So this leaves me confused moving forward as doing it that way would remove GRP roofs and increase costs of materials.
All the videos are awesome. Prefer the long ones mainly coz it keeps me entertained 😊
Nice one, Logan! Hope you're well mate.
Really appreciate the thermal fixing explanation and model. I've used the wafer head screws and you're right, you see them everytime there's a frost and the heat transfers through the screws.
Well there you go, mate. Every time you can see them in the frost that's heat escaping and simultaneously damaging the roof covering! No worries man! How's things anyway?
Thanks guys great video.
No worries, Pat. Thank you for watching.
Another great detailed video, well done.
Nice one, Barry. All the best, mate.
Great video 👍
Thank you, Nick. Hope you're well mate.
Great video well explained
Thank you, Victor. Hope you're well, mate.
Happy birthday!!! Thanks for yet another well produced, informative video
Thank you, Matthew! No worries at all. Take care.
Happy birthday Adam. Top man
Moon man!!! Haven't heard from you for a while mate! Hope you're well, pal. All the best.
Happy Birthday Adam great video
Thank you, Phil! Appreciate that mate. Hope you're well.
Happy Birthday Adam. Good video, well presented as usual. Cheers guys.
Thank you, Woody. Nice one, mate.
Superb video gents. Really appreciate you taking the time to explain this in detail. Been following your videos for a while now and I can honestly say you guys do not cut corners, the care and attention to detail is amazing, like your doing the job on your own home. You have helped an avid self builder massively grow in confidence. Thanks and keep up the great work
Gav that's great to hear mate. Thank you so much! Hope you continue to watch our stuff, all the best, mate.
Thank you to you and the team for the videos , every Sunday with out fail I watch and look forward to them
Happy birthday also
Take care guys
Thank you mate! Really appreciate your support. All the best, pal.
Happy Birthday Adam. The Hello Fresh looks lovely and I will have to give it a try 🙂 Cheers dude 👍
Thank you mate! By all means do, it really is ace! I honestly mean that! Cheers, pal. All the best.
HAPPY BIRTHDAY ADAM !!! 🎉🎉🎉
Thank you mate! You've always watched and supported us and it's not gone unnoticed or unappreciated, thank you!
Happy Birthday Adam. Great videos, love watching and learning.
Thank you, Barry. Hope you're well, mate.
I am a Brit from Befordshire now living in San Diego USA. I find looking at UK made videos by you and others keep me in touch wuth the motherland. Also I found laying brick walls in gardens released my stress from work, just like Churchill did. Over here bricks are not popular!
Wow! How the hell did you get promoted from Bedfordshire to San Diego??? Don't tell me...you married up???!!! Hahaha!!!!
@@mrabuilders6723 Its a long story Adam. I am an electronics eng by training. Had a company in Britain specilaizing in RF engingeering. Sold that to retire to San Diego and be with my US girlfriend of many years. She lived in San Diego and I had been coming here since 1994 on business and got to know her. Now a US citizen, but do miss the UK at times. Had relatives who lived in Ironbridge (owned the fish and chip shop) so your program, and accent are nostalgic for me (many visits to the area and going to West Brom football matches with my cousin). I also am impressed with your work standards, explanations, ethics, and content.
Keep up the great work,
Best
Barry
Happy Birthday Adam - Nick (Southampton)
Thank you, Nick (Southampton)! Hope you're well - Adam (Smethwick)
Happy Birthday. 🍻
Thank you, Alan. I'm having a drink as we speak! All the best, mate.
@mrabuilders6723 Cheers. All the best.
Happy Belated Birthday Adam 🎂🎂🍾🍾
Thank you, Mark! Hope you're well mate.
Happy Birthday Adam 🎉
Thank you, Pat. Appreciate that, mate. Hope you're well.
Very nice job. I've seen false parapets before, PIR horizontally flush up to external face (over cav insulation) then timber parapet on top. If I find the detail, happy to share.
Please do mate, our email address is in our bio. Thank you.
@@mrabuilders6723 Will do, be with you in a few mins 👍
sweet. a new video to watch after i watch ep 7. perfect on a crummy rain day/
Well...it's a bit of a re-edit to give people a better and easier chance to find the information, but we'd appreciate the view if you don't mind! Thank you!
@@mrabuilders6723 hell yeah im gonna watch it. love watching my brit boys build some shit.
Got any mates that work on the South Coast? I want a cold roof converted to a warm rood and have no idea who to trust. Pretty on the outside doesn't mean the inside has been done well. I can see you care about both.
Also it seems to me that the most important place in the makeup of the roof components for the VCL vapour control layer is for it to be fitted on the underside of the joists. I have specified SIGA Majrex VCL which has a dual surface that copes with moisture in two different ways, avoiding any problems with interstitial condensation on the underside of the OSB under the GRP/EDPM (this is the most common cause of flat roof failures - not punctures)
Hello again, Nicholas. Whatever you do, do not put the vapour barrier under the joists for a warm deck. It's a massive no no. Follow the instructions of this video, don't deviate from them and it'll be the best that it can be.
@@mrabuilders6723 Another thing I use to avoid thermal transfer and potential dew point/interstitial condensation issues is custom steel lintels with thermal break pads and fabricated brackets holding a galvanised angle which carries the outer skin. It is a new way to replace the traditional welded plate.
Happy Birthday 🎉
Cheers, Tom!
Great video lads. Exactly what I was looking for. All the details. What’s the expected life span on this ? Doing my extension next month and undecided on what type of finish to do on flat roof
Cheers mate, appreciate that. You'll get 25-30 years out of this, can't see why not!
Hello both. 2 questions please. 1) Theres a lot of strand board used on the layers of that roof. Is it a warm roof solely because you need 150 mmm insulation making cold roof impractical. 2) How did you transfer the rafter centres up to the roof 🤔 . Thanks 🙏
The answer to question two is simply just measure off a fixed point then go underneath and see if you can see a screw poking through, if you can't then you've hit the rafter! As for question 1, it's all about the height of the roof and what you can get away with which we will go through hopefully in the next episode.
Happy Birthday
Thank you, Matthew. Hope you're well, mate.
Happy Birthday 🍰🍷🍺
Thank you! Nice one, mate!
Happy birthday! Wondering what you think about the theory which says that you ideally shouldn't use a top deck of OSB because it's on the cold side of the roof and more susceptible to condensation and rot. Better to just have the roof covering directly bonded to the insulation. Also heard that foil faced insulation isn't the best thing to use either, because the foil facing acts as a vapor barrier and you only really want one vapour barrier in the system, otherwise you can potentially trap water vapour in the middle of the system. Needs to be hard for water vapour to get in, easy for it to get out.
Thank you, Ewan. I don't really buy into that to be honest but I'd happily be shown and proved wrong, always willing to learn!!! One of the main issues there is how do you fix the insulation down? We all know that it's not the strongest of materials. Also, the only thing holding your roof covering on is the glue between the PIR and the foil or the fabric type stuff. I won't be charging people for that anytime soon!
@@mrabuilders6723 Where I've seen it done they just seem to use the same thermally broken fixings as you did here, the large "washer" on the top should help spread the load a bit. It's not the strongest, but even in this video you guys are walking around on it without much cause for concern. It's really not that different to the stuff you use under a concrete floor.
I may have missed something but have you incorporated a secondary fall in the firrings to ensure the surface water sent down the deck then goes (perpendicular direction) downhill to the outlet?
Hello Nicholas, yes we have and all that is explained in the previous 2 videos to this one. In those videos you'll see the installation of the diminishing battens and the firring strips. Feel free to check them out. Take care.
Happy Birthday Adam for 30th, which is my Birthday too😁
Haha! Well there you go! Happy birthday! Hope you had a great day?
What about applying the fibreglass? I’d be interested in seeing that part.
That'll be in our next video, weather permitting it'll feature in this Sunday's episode.
Super!
Thanks for another great video. Just started a warm deck today. I’m always confused with the vapor barrier. So it stops all the condensation from the insulation soaking the deck below but what happens to all the moisture? Does it just stay trapped forever? 😆
Think its to stop moisture from inside the building condensing on the underside of the top deck and rotting it.
Hello Dom, hope you're well, mate. The vapour barrier is to create an air tight seal from the bottom deck upwards. The whole point of it is so the heat within the room below stays there and can't pass through. That's why we screw through into the rafters, it's to try and maintain the integrity of the vapour barrier and not rely on its "self sealing' properties.
That's sort of it, mate.
Just out of curiosity, the detail for the timber upstand - does it require vcl internally to prevent mositure laden air from entering into the space. If so, how do you achieve it, is it a simple case of adhering to the inner face of block work and underside of deck around the perimeter?
Hello, hope you're well. If I've understood the question properly...no. We want the air that's in the room to do one of two things...stay in it by not passing through the vapour/make up of the warm roof, or go through the wall and up into the insulated cavity where the only place that it can meet the cooler air of the outside is the very top of the parapet which is beyond the perimeter of the room thus not being an issue. Does that make sense?
How do you cost a job like this. Be nice if you could find the time to explain. Thanks. Keep up the great videos.
Honest answer...guess!
Hi Adam, at point 10min on the video Rich was talking about the fixings being 161mm overall, but the total depth of the insulation and OSB would be 176mm ?
Hello Kevin. The thermally broken fixings are 100mm and the screws are also 100mm, so over all when it's all clamped down you've got about 190mm. Obviously you can use longer screws providing the heads fit down the shaft of the plastic fixings!
My plan is to use a separate primer/self adhesive vapour barrier.
There's really no need.
Unfortunately i am doing a passivhaus. I’d also recommend 3.4 aircrete blocks instead of thermalites.
I wish you all the best.
😅@@TMZ-5jr
Could you use 18mm OSB instead of 11 mm therefore countersink the plastic thermal fixings hense have a flatter deck for the GRP ? Love to hear your thoughts ?
Hello Glenn. It's not impossible mate, but the heads of the fixings are approx 5mm if not more, definitely not less, and you'll have to go deeper as to have room to fill over them afterwards, so there's not a lot of meat left to confidently fix down to if that makes any sense?
We do this and use 18mm t&g OSB3. We use a countersink and take out approx 4mm. We thought about filling them in after but have not needed to and you can’t see any fixings. Good idea though to fill fixing hole with foam like they do on this video. But have to agree if you try to do that on 11mm boards you wont have much meat left to confidently fix down. Have to say this video they made is the best one I have seen on here
The best roof possible would be one with an epdm covering. The title i submit is misleading.
Go on...I'll bite...how would EPDM be more efficient?
🤣
@@mrabuilders6723 I'm not referring to the thermal properties but the many advantages it has as a top covering over and above that provided by fiberglass.
I don't have any real issues with the construction from a thermal efficiency perspective.
@paulf2529 oh right. Fair enough. You prefer the patchy, many weak points kinda finish. Fair play.
@@mrabuilders6723 like anything it depends on how well it is carried out. Personally I have seen first hand many bad fiberglass installations and i doubt these will get anywhere near the quoted life expectancy.