Thanks for watching! Here is a link to the Vapour Barrier we used for this project: www.rubber4roofs.co.uk/alutrix-vapour-barrier use our DISCOUNT CODE ROOFSCOUT5 for 5% discount on all flat roofing materials!
Are you two cowboys still operating with foil back pir boards in a warm roof? You should be dam ashamed of yourselves. Even more so putting your ways online. It's a joke. Why no more vids ? Because your channel will stay stagnent when you talk nonsense. How many court cases have you had to date using foil back pir in a warm roof ? Be honest !! Seriously boois you would want to rectify this or your going to get sued worse than the spray foam worzols that spray direct with no vent card.
@@Roofscoutyou really used foil back pir after your vapour barrier in a warm roof build up. Back to school boys...... And mate you might want to go back to your customers and rectify your work . Your find yourself in major court battles in the years to come and you'll have to replace the whole building .., just saying. Why you primed and laid one of the best Vapour barriers on the market down properly and on the internal side of insulation. Only to Sela it all in again and trap moisture using frigging foil back pir boards . Lads it's for reflecting heat in the slabs . That's what it is designed for. If you didn't burst the foil then you are screwed. Edit .,. You absolute donkeys. How dare you call yourself tradesmen. You taped the foil. Bahhahhahhhhhh O dear. O dear.
What is your option on what most roofing manufactures are saying the top osb3/ply should not be used and the roofing product fixed directly onto the insulation. Also the correct flat roof insulation is not foiled back if adhering or torching on the top cover. It must be fleece backed such as the kingspan Thermaroof TR26 or TR27. Full detailed descriptions of the technical reasons I can quote from them. But the short of it is that the top cannot absorb or disperse the heat and is subject to below-ambient low temperatures. So subjects the material to moisture vapour cycles which repeatedly condenses and evaporates on its surface, so in time the top deck will rot and compromise the performance of the system.
Hi Mert Thanks for watching and for your comments we're glad you enjoyed the video. We do have plenty of other videos on waterproofing layers such as Resitrix that was used on this roof. and many more to come on our channel. Please check them out subscribe to our channel as we'd love your feedback in the future.
Thankyou for this video.. one question. By screwing through the top 18mm osb sheet and through the insulation to the joists below. Are you not piercing the vapour barrier. Again thanx for the vid xxx
Hi Ian Thanks for watching! Unfortunately due to time constraints we were unable to film the waterproofing layer being fitted on this roof. In terms of finishing up against the wall we took the membrane 150mm up the wall and as the wall was being re-rendered the render was laid over the membrane down to deck level. We do have a few other videos showing how we've chased into the wall and finished with a metal wall trim however. I hope this helps.
couple points, the VCL should be brought up and over the skylight upstand, stopping short allows vaput straight into the insulation. No need to use OSB on top of the insulation or firring strips. Kingspan thermataper has falls built in and can take EDPM directly. Lastly you didnt insulate to the top of the upstand, BCO should fail that.
In the old days the vapour barrier used to be thin gauge polythene but I always question the use of a vapour barrier if your going to pepper it with screw holes
I can't believe driving screws straight into the vapor guard passes inspection in the UK. UK roofs are quite far behind when it comes to warm roofs, you can glue your insulation right onto the vapor guard same as the membrane. That OSB isn't needed.
@Matt01miller you are quite right. All my research says glue the insulation down. Should not use OSB to the top of insulation it will rot but what I can’t find is which insulation is suitable to apply the three layer bitumen felt. Can you use any PIR of 150mm for instance?
@saharasultana4172 you can use any really, the first layer of felt is the vapour guard, then insulation, then 2 layers of felt, ideally 9mm thick total. The first layer on top is cold adhesive so the flame doesn't melt the insulation.
If you just seal the top of the pir and you have some air leakage the warm air will condense between the insulation and potentially rot out the plywood/osb underneath, similar to SIPS. The vapour/air barrier being installed beneath the insulation (the warm side) is best practice and reduces the possibility of air leakage entering the insulation to begin with
@@eddieduff9740 in my understanding just use non foil pir and use the same process then in video. The vapour barrier need s to be the internal side of the insulation. No foil back pir can be used.
Exactly bro. This roof is going to fail but in about 5 to 10 years. No foil back to be used in warm roof. Hybrid or cold roof yes but defo not warm ,.. The process these have used is a major no no. Use rigid board but no blooming foil back. Lunatics are trapping all the moisture where you really do not want it. Xxxx
@@TheDeanoc69 no . Wow . Buddy. One vapour barrier . God help you or your customers if you have put foil back insulation on top of your vapour barrier for a WARM roof. God help you bro. And mate do some reading and maybe lay a few roofs before coming at me. This is not the way to do it. I repeat this is not the way to do it.
What is the size of that long screw you use at the top of the plywood? What is the spacing between long screws around the perimeter and between inner? Thanks
Do the boards on the upper deck need to line up with and finish to the rafters below? Exact positioning is only approximate so can the boards butt between rafters?
@baldyslapnut. I have never had a call back through cold bridging neither have building control asked for these fixings. They spec joist, firring, 11mm osb. Vapourbarrier. 150mm pir. 18mm osb screwd threw into joists with 250mm screws. No concern of piercing vapour barrier or cold bridging. I have done this method for well over 10 years.
Hi there, Would you mind me asking you,... I'm doing it on my own and the weather has been the main factor to watch out. I've laid the first sheathing which took me the whole day.... How long did it take you to lay the deck from start to finish? Many thanks!
There is a expensive version of PIR for flat roofs. Does it make any difference? For example: 120mm Recitcel PowerDeck Flat Roof Insulation Board 1200mm x 600mm is double the price per square meter compared to 120mm Recticel Eurothane Insulation Board 2400mm x 1200mm
Hi fellas great video, you make it look really easy,l bet your great at wrapping Christmas presents 😂 question for you , got a warm room to do on my own property but it will be walked on regularly, what surface would you recommend to finish it with
Hi John If you are using the roof as a balcony you could install an EPDM membrane and then install some form of decking or balcony tiles over the top. Make sure to protect the membrane with some geotextile fleece before laying anything over the top though!
Hi ComeWhatThey Thanks for watching. We agree, that is one way of constructing a warm roof however there are also benefits to our chosen method. A lot of EPDM systems aren't recommended to be bonded directly to tissue faced insulation therefore the extra layer of OSB is needed. This also means the foil backed insulation is fine as we did not adhere the waterproofing membrane to this. Another benefit of the top deck is that it is more hard wearing providing a nice solid base. If the house roof ever needs to be accessed via the flat roof, there is now a nice solid base for any ladders or foot traffic. This would not be possible if we'd adhered directly to tissue faced insulation. The benefit of thermally broken fixings in comparison to those we used is minimal in terms of how they impact the U-value of the roof.
@@Roofscout Thermal fixings aren't to improve the u value overall, they're to reduce cold bridging. And the issue with foil isn't just poor adhesion, it's acting as a vapour barrier on the wrong (cold) side of the roof, further helping your upper deck to rot over time. You can often get away with it but there's really no reason to have an upper deck in most cases, it's fine for limited access without one and it's just added expense for the customer.
Are there any issues if i build a warm roof on top.of the exisiting felt (provided its all dry) forgoing taking the felt off and adding vapour barrier and then doing rubber roof? Cheers guys, great informative video
Good video - but you could have saved the client a bit of money.... osb acts as a vapour barrier, just needed to tape the joints. Also, was the waterproof membrane EPDM? It could have gone over the insulation without yet another layer of osb...
@@johnsonkevin1 Yes it does. I learned this working on Passivhauses and have employed it many times since. If used on the warm side and the joints are taped. Not an airtight layer, but certainly as a vapour barrier. And EPDM can be laid over polyisocyanurate (PIR) insulation, perhaps not the foiled stuff - I don't know about that - but it can be either adhered or mechanically fixed.
Great video format, easy to follow. Are there any alternatives to the self-adhesive-vapor-barrier products on the market? Most of the stuff I can find is £60 for 10M. No doubt it makes a great job, but at a cost. Would a torch-on felt-underlay suffice?
Hi ChAzZ Thanks for watching, we're glad you enjoyed the video! The Torch on Felt Underlay would suffice however specific Vapour Barriers like the ones we used are much better suited and easier to install. The Alutrix 600 Vapour Barrier self seals around the deck screws we used to fix the top board through to the joists for instance.
Technically you can use a polyethylene sheet, 500ga or greater. But you have to fix it with staples which obviously puncture the surface and reduce its effectiveness a little.
@@ComeWhatThey Thanks for the reply guys, it's great to hear different ideas from people. I've also heard about polyethylene sheeting too. But as you say, puncturing... but then again, don't the 150mm long screws that sandwich everything together puncture the membrane anyway?
@@ChAzZMaNZZ Yes they do. Alutrix is a nice product but of course it's a bit ridiculous to suggest that warm roofs don't work without it. Just have to take care with installing polyethylene, and tape over any punctures/rips.
If I was going to install a roof I would first of all ask myself where the water vapour from inside is going to go.. Secondly I would ask myself what happens when it rains When I have logical answers then I would spend some time thinking about roof options
Hi need help. Is OSB wood or structural Plywood better suited for a summer house roof? I see everyone is using OSB, but my handy man recommends structural plywood but it is about £150 - £200 more. I'll also be covering the roof with EPDM rubber membrane.
Top sheet of ply is a big no no and has been for quite a while - this will be the big failure point , it’s basically a cold roof with zero ventilation also if mech fixing the installation all fixings need to be thermally broken
@@danny1977 I’m in Suffolk I own a roofing company with 6 full time installers only doing flat roofs covering Suffolk north Essex and Norfolk- I can categorically tell you the don’t -anyone reading this don’t cover insulation with ply it will fail regs and crumble away within 5-7 years
@@ianedwards9735 This guy knows what he’s talking about, spends lots of his time fixing flat roofs cowboys have installed th-cam.com/video/RthYYgzhMWU/w-d-xo.html
Hi Danny Thanks for watching. This is roughly a days work between 2 people. It did take us slightly longer than it usually would due to filming the job though.
As kingspan is so expensive would you be able to use 120mm celotex as a cheaper alternative for the insulation?or what cheaper alternative would you suggest please .
If you mean the vapour barrier it’s to stop water vapour entering from the room below and then condensing on the cold side of the insulation i.e the top of the insulation just below the waterproofing layer.
How many layers do you need to trap moisture in? There should be only one - the first layer of OSB. No vapour barrier, no ply on top ffs. This will rot phenomenally.
Hi Tanel Thanks for your comment. There is no way of moisture entering the roof cavity as there is a vapour barrier to prevent rising moisture entering the roof build up from the room below. There is also a waterproofing membrane installed to this roof preventing water entering the build up from above.
@@Roofscout knowledge of basic construction physics would help - there is no way to make the vapour barrier underneath 100%. In addition, there will always occur condensation.
So what happens if i want to make a terrace there? How do i put tile or some decorative thing on the floor of the terrace? And how does a flat roof drain if it rains? Cause if its flat and leveled, and not on a slight slope, how does the water run off? Cause if we make a slight slope, wouldnt that look like a crooked roof from far away if u look at it?
Hi Milena Thanks for watching! This would all depend on the waterproofing membrane you are using on top of the top deck of the roof. For example if you are using Epdm you would screed over the membrane and then you could tile on top of the screed. Another option would be to lay decking on top of the waterproofing membrane but I would discuss this procedure with the supplier of the waterproofing membrane beforehand. Every flat roof should have a slight fall on it to aid drainage. The roof in the video falls toward the front edge where the guttering was later installed.
@@mindematt you don’t need to vent warm roofs but here the roofer has applied a OSB deck on top of insulation so a cold roof on a warm roof. He needs to vent this? Otherwise it will rot? Just a question as I am learning and could be wrong.
I'm not a roofer. Was asked by determined client t finish his flat roof with skylight, he selected 22mm marine ply above joists/furrings which he's already layed, now wants Visqueen Vapour Barrier, then 9mm OSB, then taping, trims and fiberglass. With all the rain we've had over the last few weeks and the marine ply being absolutely soaked what problems can you foresee? I've already told him multiple times that I'm NOT a roofer, but that he should have used OSB from the get-go... Any help Plus fibreglass can't be layed even if it's damp
Hi criollitoification If there is moisture within the roof build up and you add a waterproofing membrane of any kind before the whole build up is completely dry the trapped moisture can lead to an array of issues such as bubbling in the waterproofing membrane. I would ensure all Timber is completely dry before installing the remaining components. The marine ply may not be a major issue for the lower deck but many GRP/Fibreglass manufacturers recommend using osb3 T&G boards nowadays as the GRP is less likely to fail on the board joints with T&G boards and GRP adheres well to OSB. If you have no experience using a Fibreglass system I would try to avoid it in all honesty as the detailing work can be tricky and if not done correctly it will need to be ripped up and the boards will need replacing making any errors quite costly. You could try suggesting/using EPDM as an alternative. As a system a rubber roof is a lot more forgiving than Fibreglass as there is no working time (once catalysed GRP must be installed before it goes hard). We have plenty of videos on this system that you may find useful. If the client is adamant that they want a Fibreglass roof, our best advice would be to contact an experienced professional. I hope this helps and thanks for watching our videos!
Hi Martin We hope you're well. We're sorry to hear you don't approve of our installation but this roof complies with Building Regulations and was passed off by Building Control. We understand every Roofer may have their own way of doing things and their own personal preferences but as mentioned this roof is up to spec. Thanks for watching again.
Hi tinkletoesrus A warm deck flat roof refers to a construction method where the insulation is installed on top of the roof deck, creating a warm barrier. This means that the deck and insulation are kept warm, preventing the formation of condensation and potential damage. On the other hand, a cold deck flat roof has insulation placed between or below the roof joists, allowing the deck to be colder. In this setup, condensation can occur on the underside of the deck if proper ventilation is not provided. In summary, the key difference lies in the placement of insulation. Warm decks keep the deck and insulation warm, while cold decks allow the deck to be colder, potentially leading to condensation issues. The choice between the two depends on factors like climate, building regulations, and specific requirements. 🏠❄️🌡️
Thanks for watching! Here is a link to the Vapour Barrier we used for this project: www.rubber4roofs.co.uk/alutrix-vapour-barrier use our DISCOUNT CODE ROOFSCOUT5 for 5% discount on all flat roofing materials!
Are you two cowboys still operating with foil back pir boards in a warm roof? You should be dam ashamed of yourselves. Even more so putting your ways online. It's a joke. Why no more vids ? Because your channel will stay stagnent when you talk nonsense. How many court cases have you had to date using foil back pir in a warm roof ? Be honest !! Seriously boois you would want to rectify this or your going to get sued worse than the spray foam worzols that spray direct with no vent card.
Love the no nonsense format guys. Well done.
This was very helpful and full of detail. Greatly helped me with my school construction project on this roof type. Thank you
Hi McGinty
That's great! we're glad you found our video useful.
@@Roofscoutyou really used foil back pir after your vapour barrier in a warm roof build up. Back to school boys...... And mate you might want to go back to your customers and rectify your work . Your find yourself in major court battles in the years to come and you'll have to replace the whole building .., just saying. Why you primed and laid one of the best Vapour barriers on the market down properly and on the internal side of insulation. Only to Sela it all in again and trap moisture using frigging foil back pir boards . Lads it's for reflecting heat in the slabs . That's what it is designed for. If you didn't burst the foil then you are screwed. Edit .,. You absolute donkeys. How dare you call yourself tradesmen. You taped the foil. Bahhahhahhhhhh O dear. O dear.
What is your option on what most roofing manufactures are saying the top osb3/ply should not be used and the roofing product fixed directly onto the insulation. Also the correct flat roof insulation is not foiled back if adhering or torching on the top cover. It must be fleece backed such as the kingspan Thermaroof TR26 or TR27.
Full detailed descriptions of the technical reasons I can quote from them. But the short of it is that the top cannot absorb or disperse the heat and is subject to below-ambient low temperatures. So subjects the material to moisture vapour cycles which repeatedly condenses and evaporates on its surface, so in time the top deck will rot and compromise the performance of the system.
This was very helpful. Short, to the point, full of detail. Thanks!
Glad it was helpful!
@@Roofscout does it need any vent holes in the voids in the joists and also is there a spec for joist timber size vs extension size, thanks
Should I be finding an even smaller roller for the primer? Looks like the ones you guys are using are way too big
The vapour barrier should be on the inside of the upstand, it's to keep internal moisture laden air out of the insulation.
It would be good to know what happened around the pipe. Is there a pipe embedded in the insulation?
Hi, good tutorial. Can you put extra insulation between the rafters/joists underneath the warm roof
No then it becomes a cold roof and needs to be ventilated
Very good job done, but where would the water drain of because the pipe is a little bit higher to the insulation. Thanks 🎉
Great video guys, no messing!
When I see 'start to finish', I actually would like to see a finishing. This i's also quick and useful, thanks.
Hi Mert
Thanks for watching and for your comments we're glad you enjoyed the video.
We do have plenty of other videos on waterproofing layers such as Resitrix that was used on this roof. and many more to come on our channel.
Please check them out subscribe to our channel as we'd love your feedback in the future.
Thankyou for this video.. one question. By screwing through the top 18mm osb sheet and through the insulation to the joists below. Are you not piercing the vapour barrier.
Again thanx for the vid xxx
m.th-cam.com/video/tufzI-1xTJQ/w-d-xo.html
At about 13 minutes
Do you have a video of the final layer? Would love to see the torch on felt method on warm roof
Do you have a follow-up video of the flat room being completed? It more about I'd like to know how to finish the sides to the brick.
Hi Ian
Thanks for watching! Unfortunately due to time constraints we were unable to film the waterproofing layer being fitted on this roof.
In terms of finishing up against the wall we took the membrane 150mm up the wall and as the wall was being re-rendered the render was laid over the membrane down to deck level.
We do have a few other videos showing how we've chased into the wall and finished with a metal wall trim however.
I hope this helps.
couple points, the VCL should be brought up and over the skylight upstand, stopping short allows vaput straight into the insulation. No need to use OSB on top of the insulation or firring strips. Kingspan thermataper has falls built in and can take EDPM directly. Lastly you didnt insulate to the top of the upstand, BCO should fail that.
No thermally broken fixings as well
I was wondering about the upstand creating a thermal bridge along the house wall
Brilliant
Can you show us slop of warm roof . So how rain water goes
Can I put an Osb deck over a concrete deck? Or just attach the membrane on to the concrete?
Excellent. Thanks.
No problem Nikki!
Thanks for watching!
Is there a video showing how you install the roof joists onto the walls?
In the old days the vapour barrier used to be thin gauge polythene but I always question the use of a vapour barrier if your going to pepper it with screw holes
This self-adhesive vapor barrier is very expensive I would just use what you've just pointed out.
😂😂😂
Great content Lads 👍
Thank you and thanks for watching 👍
I can't believe driving screws straight into the vapor guard passes inspection in the UK. UK roofs are quite far behind when it comes to warm roofs, you can glue your insulation right onto the vapor guard same as the membrane. That OSB isn't needed.
@Matt01miller you are quite right. All my research says glue the insulation down. Should not use OSB to the top of insulation it will rot but what I can’t find is which insulation is suitable to apply the three layer bitumen felt. Can you use any PIR of 150mm for instance?
@saharasultana4172 you can use any really, the first layer of felt is the vapour guard, then insulation, then 2 layers of felt, ideally 9mm thick total. The first layer on top is cold adhesive so the flame doesn't melt the insulation.
@@saharasultana4172
No it doesn’t
What's the point of a vapor barrier when the pir boards are 100% vapor closed due to the aluminium layer on both sides?
If you just seal the top of the pir and you have some air leakage the warm air will condense between the insulation and potentially rot out the plywood/osb underneath, similar to SIPS. The vapour/air barrier being installed beneath the insulation (the warm side) is best practice and reduces the possibility of air leakage entering the insulation to begin with
@@eddieduff9740 in my understanding just use non foil pir and use the same process then in video. The vapour barrier need s to be the internal side of the insulation. No foil back pir can be used.
Exactly bro. This roof is going to fail but in about 5 to 10 years. No foil back to be used in warm roof. Hybrid or cold roof yes but defo not warm ,.. The process these have used is a major no no. Use rigid board but no blooming foil back. Lunatics are trapping all the moisture where you really do not want it. Xxxx
@@worz678wow are you kidding me?! This process is exactly the way to do it lol
@@TheDeanoc69 no . Wow . Buddy. One vapour barrier . God help you or your customers if you have put foil back insulation on top of your vapour barrier for a WARM roof. God help you bro. And mate do some reading and maybe lay a few roofs before coming at me. This is not the way to do it. I repeat this is not the way to do it.
What is the size of that long screw you use at the top of the plywood? What is the spacing between long screws around the perimeter and between inner? Thanks
Do the upper boards need to line up (finish) with the rafters below or can they join between rafters?
Do the boards on the upper deck need to line up with and finish to the rafters below? Exact positioning is only approximate so can the boards butt between rafters?
it looks like nextdoors extension is onto your boundry / land by about a foot?
Is it usual for them to leave the old felt on the roof then do this on top with felt again on top?
Shouldn't the insulation space be vented?
What I've always been confused by is how is the osb that the insulation is on not a cold spot issue?
Hiya did you not use insulated plastic dowels to screw through the insulation to stop the reduction of the thermal barrier?
Cold bridging through a 5mm screw shank?.
@@slipper150Look at in the next frost. Yes, there will be cold bridging even with 5, 6, or 8mm screws. The mushroom fittings are made for a reason🙄
@@baldyslapnut. doubt it
@@slipper150 Doubt all you want, it's basic physics.🙄
@baldyslapnut. I have never had a call back through cold bridging neither have building control asked for these fixings. They spec joist, firring, 11mm osb. Vapourbarrier. 150mm pir. 18mm osb screwd threw into joists with 250mm screws.
No concern of piercing vapour barrier or cold bridging. I have done this method for well over 10 years.
Hi there, Would you mind me asking you,... I'm doing it on my own and the weather has been the main factor to watch out. I've laid the first sheathing which took me the whole day....
How long did it take you to lay the deck from start to finish? Many thanks!
There is a expensive version of PIR for flat roofs. Does it make any difference?
For example: 120mm Recitcel PowerDeck Flat Roof Insulation Board 1200mm x 600mm is double the price per square meter compared to 120mm Recticel Eurothane Insulation Board 2400mm x 1200mm
Proper job 👍
nicely done. although! haha. the upstand for the skylight looks like it could be shy of 150mm at the lowest side ;) lol... always one
Thanks for watching!
Haha That may just be the camera angles, it was definitely a minimum of 150mm all the way around 👍.
Hi fellas great video, you make it look really easy,l bet your great at wrapping Christmas presents 😂 question for you , got a warm room to do on my own property but it will be walked on regularly, what surface would you recommend to finish it with
Hi John
If you are using the roof as a balcony you could install an EPDM membrane and then install some form of decking or balcony tiles over the top.
Make sure to protect the membrane with some geotextile fleece before laying anything over the top though!
Should be using thermally broken fixings rather than those long screws, non foil faced insulation and no upper deck of OSB. Good other than that.
Hi ComeWhatThey
Thanks for watching.
We agree, that is one way of constructing a warm roof however there are also benefits to our chosen method.
A lot of EPDM systems aren't recommended to be bonded directly to tissue faced insulation therefore the extra layer of OSB is needed. This also means the foil backed insulation is fine as we did not adhere the waterproofing membrane to this.
Another benefit of the top deck is that it is more hard wearing providing a nice solid base. If the house roof ever needs to be accessed via the flat roof, there is now a nice solid base for any ladders or foot traffic. This would not be possible if we'd adhered directly to tissue faced insulation.
The benefit of thermally broken fixings in comparison to those we used is minimal in terms of how they impact the U-value of the roof.
@@Roofscout Thermal fixings aren't to improve the u value overall, they're to reduce cold bridging. And the issue with foil isn't just poor adhesion, it's acting as a vapour barrier on the wrong (cold) side of the roof, further helping your upper deck to rot over time. You can often get away with it but there's really no reason to have an upper deck in most cases, it's fine for limited access without one and it's just added expense for the customer.
Hi mate did you lay a rubber membrane on top?
Thanks
What was the self adhesive vapour barrier and primer?
Hi Steve
We used the Alutrix 600 Vapour Barrier with FG35 Primer 👍.
Are there any issues if i build a warm roof on top.of the exisiting felt (provided its all dry) forgoing taking the felt off and adding vapour barrier and then doing rubber roof?
Cheers guys, great informative video
The felt is fine as a vapour barrier if its not split or any holes etc.
Screwing through the VCL.
Good video - but you could have saved the client a bit of money.... osb acts as a vapour barrier, just needed to tape the joints. Also, was the waterproof membrane EPDM? It could have gone over the insulation without yet another layer of osb...
OSB does not act as vapour barrier.
EPDM can not be layed over foiled PIR
@@johnsonkevin1 Yes it does. I learned this working on Passivhauses and have employed it many times since. If used on the warm side and the joints are taped. Not an airtight layer, but certainly as a vapour barrier.
And EPDM can be laid over polyisocyanurate (PIR) insulation, perhaps not the foiled stuff - I don't know about that - but it can be either adhered or mechanically fixed.
Hse will want to know why you have no edge protection.
Easy now big cheese, save that kinda chat for the parties
Bore off
Great vid, curious, what’s the cost to have this done. Looking to replace ours with a solid roof
I reckon it was about 3000K, using OSB3 which is way cheaper than plywood, cheaper insulation, then the most costly -> allutrix and resitrix .
Was the flat roof for a permitted development extension..?
Hi RS
No this extension did require planning permission.
Great video format, easy to follow. Are there any alternatives to the self-adhesive-vapor-barrier products on the market? Most of the stuff I can find is £60 for 10M. No doubt it makes a great job, but at a cost. Would a torch-on felt-underlay suffice?
Hi ChAzZ
Thanks for watching, we're glad you enjoyed the video!
The Torch on Felt Underlay would suffice however specific Vapour Barriers like the ones we used are much better suited and easier to install. The Alutrix 600 Vapour Barrier self seals around the deck screws we used to fix the top board through to the joists for instance.
Technically you can use a polyethylene sheet, 500ga or greater. But you have to fix it with staples which obviously puncture the surface and reduce its effectiveness a little.
@@ComeWhatThey Thanks for the reply guys, it's great to hear different ideas from people. I've also heard about polyethylene sheeting too. But as you say, puncturing... but then again, don't the 150mm long screws that sandwich everything together puncture the membrane anyway?
@@ChAzZMaNZZ Yes they do. Alutrix is a nice product but of course it's a bit ridiculous to suggest that warm roofs don't work without it. Just have to take care with installing polyethylene, and tape over any punctures/rips.
You can pay £300 for 40M2 of Alutrix, or you can pay £20 for 40M2 500GA Polythene. Worst case scenario, you will save 90% if you go with Polythene.
What sort of thickness of OSB board would you recommend for a garden studio re-roof. Can I use any OSB board to lay EPDM rubber on top of? Thanks :)
18mm
If I was going to install a roof I would first of all ask myself where the water vapour from inside is going to go..
Secondly I would ask myself what happens when it rains
When I have logical answers then I would spend some time thinking about roof options
Hiya, what size is the insulation you have used please?
What vapour barrier did you use?
Hi need help. Is OSB wood or structural Plywood better suited for a summer house roof? I see everyone is using OSB, but my handy man recommends structural plywood but it is about £150 - £200 more. I'll also be covering the roof with EPDM rubber membrane.
18mm osb
Top sheet of ply is a big no no and has been for quite a while - this will be the big failure point , it’s basically a cold roof with zero ventilation
also if mech fixing the installation all fixings need to be thermally broken
True mate.
CNC BUILDING CONTROL insist on it where I live and they cover cambs ,norfolk and Suffolk?
@@danny1977 I’m in Suffolk I own a roofing company with 6 full time installers only doing flat roofs covering Suffolk north Essex and Norfolk- I can categorically tell you the don’t -anyone reading this don’t cover insulation with ply it will fail regs and crumble away within 5-7 years
@@ianedwards9735
This guy knows what he’s talking about, spends lots of his time fixing flat roofs cowboys have installed
th-cam.com/video/RthYYgzhMWU/w-d-xo.html
What if your torching felt? Dont you need the the top layer of osb3 for that?
How long from start to finish the roof?
Hi Danny
Thanks for watching.
This is roughly a days work between 2 people. It did take us slightly longer than it usually would due to filming the job though.
@@Roofscout wow that's impressive m8 I'm currently building a flat roof extension so I was wondering timescale thanks for replying 😀
As kingspan is so expensive would you be able to use 120mm celotex as a cheaper alternative for the insulation?or what cheaper alternative would you suggest please .
Celotex and kingspan are very similar in cost
Same product different name
@@macsmith6216one is £200 a sheet the other is £55 ???
What is the actually purpose of the membrane . If water ever built up wouldn't it just turn into a pool of water
If you mean the vapour barrier it’s to stop water vapour entering from the room below and then condensing on the cold side of the insulation i.e the top of the insulation just below the waterproofing layer.
How much? South Yorkshire
How many layers do you need to trap moisture in? There should be only one - the first layer of OSB. No vapour barrier, no ply on top ffs. This will rot phenomenally.
Hi Tanel
Thanks for your comment.
There is no way of moisture entering the roof cavity as there is a vapour barrier to prevent rising moisture entering the roof build up from the room below. There is also a waterproofing membrane installed to this roof preventing water entering the build up from above.
@@Roofscout knowledge of basic construction physics would help - there is no way to make the vapour barrier underneath 100%. In addition, there will always occur condensation.
There should not be a timber cover placed over the insulation.
No fall arrest, wow
hello on voit que vous etes des débutants car la façon que les ouvriers déroulent le rouleau
So what happens if i want to make a terrace there? How do i put tile or some decorative thing on the floor of the terrace?
And how does a flat roof drain if it rains? Cause if its flat and leveled, and not on a slight slope, how does the water run off? Cause if we make a slight slope, wouldnt that look like a crooked roof from far away if u look at it?
Hi Milena
Thanks for watching!
This would all depend on the waterproofing membrane you are using on top of the top deck of the roof. For example if you are using Epdm you would screed over the membrane and then you could tile on top of the screed. Another option would be to lay decking on top of the waterproofing membrane but I would discuss this procedure with the supplier of the waterproofing membrane beforehand.
Every flat roof should have a slight fall on it to aid drainage. The roof in the video falls toward the front edge where the guttering was later installed.
Didn’t show cross ventilation below or a means of vent up n out. No mushroom vent or box vents.
You don't need to vent warm roof - simple as that. Cold roof where ventilation is needed.
@@mindematt you don’t need to vent warm roofs but here the roofer has applied a OSB deck on top of insulation so a cold roof on a warm roof. He needs to vent this? Otherwise it will rot? Just a question as I am learning and could be wrong.
Those 4x2's on the eves edge wern't very well screwed down gaps all along, could see the osb curve!!! You wiuldn't get a job from me!!!!
What the brand of that vapour barrier called ?!
Hi Cormac
We used the Alutrix 600 Vapour Barrier on this project.
@@Roofscout okayyy thank you for your reply appreciate it and keep up the good work !
Can't get my head around the fact you do all vapour barrier work, then put screws all over it
Hi there
The Alutrix 600 Vapour Barrier is self sealing meaning it provides a water tight seal around the penetrating screws!
I'm not a roofer. Was asked by determined client t finish his flat roof with skylight, he selected 22mm marine ply above joists/furrings which he's already layed, now wants Visqueen Vapour Barrier, then 9mm OSB, then taping, trims and fiberglass. With all the rain we've had over the last few weeks and the marine ply being absolutely soaked what problems can you foresee? I've already told him multiple times that I'm NOT a roofer, but that he should have used OSB from the get-go... Any help
Plus fibreglass can't be layed even if it's damp
Hi criollitoification
If there is moisture within the roof build up and you add a waterproofing membrane of any kind before the whole build up is completely dry the trapped moisture can lead to an array of issues such as bubbling in the waterproofing membrane.
I would ensure all Timber is completely dry before installing the remaining components.
The marine ply may not be a major issue for the lower deck but many GRP/Fibreglass manufacturers recommend using osb3 T&G boards nowadays as the GRP is less likely to fail on the board joints with T&G boards and GRP adheres well to OSB.
If you have no experience using a Fibreglass system I would try to avoid it in all honesty as the detailing work can be tricky and if not done correctly it will need to be ripped up and the boards will need replacing making any errors quite costly.
You could try suggesting/using EPDM as an alternative. As a system a rubber roof is a lot more forgiving than Fibreglass as there is no working time (once catalysed GRP must be installed before it goes hard). We have plenty of videos on this system that you may find useful.
If the client is adamant that they want a Fibreglass roof, our best advice would be to contact an experienced professional.
I hope this helps and thanks for watching our videos!
@@Roofscout thanks for the reply, I'll pass this info on to client and let him make the decision, I guess it's all I can do. Thanks again all the best
Don’t go down the GRP route mate it’s a shocker of a system,but as an asphalt & felt roofer it’s keeping me busy putting them right.
@@criollitoification
If your not a roofer why take on the job
Soon as you screw down your boards you are screwing the tape you first put down. So will sweat
?Use a bigger roller!
scaffolding for the camera man but not the roof works hehe
You missed a trick by not using thermally isolated fixings, I am sure you do on your subsequent projects since :-)
No need for osb on top of the Insulation, it will just fail in years to come, prime the insulation broads and s-vap on top then you liquid system
Also the long screws will compromise the vapor barrier everywhere they penetrate
@@younameddepends on the brand of vapour barrier . You can get self sealed that take away this issue you are thinking of.
I want mine done this way so I can walk on to. If it wasn't it would leave dents on the insulation
And this silver backing comes away from the insulation
Have seen it on many occasions
You obviously have no idea what you're talking about. Wow
That is not a warm roof.
Of course it’s not these guys are cowboys, frighting
Looks like a warm roof to me
Which one is warm deck?
100% that’s a warm roof. The insulation went on the roof didn’t it!????
@@Misterman924 In the wrong place though.
Not like this that’s for sure
Hi Martin
We hope you're well.
We're sorry to hear you don't approve of our installation but this roof complies with Building Regulations and was passed off by Building Control.
We understand every Roofer may have their own way of doing things and their own personal preferences but as mentioned this roof is up to spec.
Thanks for watching again.
@@Roofscout
I’m not sure what’s more worrying that you think this standard of workmanship is ok
Or building control signed it off
@@martinsutherland4270 What is wrong with it then, I would be interested to know
@Martin Sutherland still waiting to see your work mate? What did they do wrong? All looked good to me.
@martinsutherland4270 there's always one like you ain't there 🙄
scam artists, embarrassing
Hey guys, do you have an email?
whys is it warm
Hi tinkletoesrus
A warm deck flat roof refers to a construction method where the insulation is installed on top of the roof deck, creating a warm barrier. This means that the deck and insulation are kept warm, preventing the formation of condensation and potential damage.
On the other hand, a cold deck flat roof has insulation placed between or below the roof joists, allowing the deck to be colder. In this setup, condensation can occur on the underside of the deck if proper ventilation is not provided.
In summary, the key difference lies in the placement of insulation. Warm decks keep the deck and insulation warm, while cold decks allow the deck to be colder, potentially leading to condensation issues. The choice between the two depends on factors like climate, building regulations, and specific requirements. 🏠❄️🌡️