Rotted OSB roof decking. Cold flat roof condensation and through ventilation
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- Опубликовано: 21 сен 2024
- New flat roofs that haven't been constructed correctly take about two or three years to start to rot from the inside outwards. The new rear extension on this property is only three years old, and the roof has begun to rot away. The builders didn't construct the roof correctly its not a warm roof or a cold roof but somewhere between and because of the lack of ventilation to voids in the roof and the lack of a proper vapour control layer or VCL moister from inside has condensed to the back of the flat roof decking and this has rotted the bards away.
Humidity levels in houses are getting higher, and the attention to detail on how a flat roof or any roof is constructed is now even more critical. Black mould and fungus soon establishes its and starts the rotting process and as you can see on this video the decking under the roof membrane has completely collapsed. It's only the strength of the roof membrane that is stopping the roof from collapsing.
Top presentation as ever. Pity more people don’t know how to construct a roof to last. Keep up the good work. Pete
Excellent video, graphics and descriptions!
only the skilled worker truly knows his job: there are very few people that actually take the time and effort to become skilled.....
Yes its a sign of our times
Great job guys
THanks
if we are screwing down we don't use a primer if we are glueing down the AVCL (air vapour control layer) we use the primer that comes with the AVCL
Someone wise once said "good design isn't about how water gets into your building, it's how it gets out"
Yes, a lot of people don't realise that this is just as important
Hi Steve. I'm super interested to see how you vented the upper part of roof / abutting walls please!
how did he vent it......
He would have used something like this. It would have been much easier to vent without the parapet walls. But the whole thing looks like an amateur trying to do a good job and missing the mark.
www.roofingsuperstore.co.uk/product/type-rav-fl-flat-roof-abutment-ventilator.html?gclid=Cj0KCQiAlsv_BRDtARIsAHMGVSamQQivNFv1JFo3GA8nOdJggcN3ziViFQDz6Vvj6bUsGlsBDiqMLkYaAlSLEALw_wcB
Great vid, just fell across your channel. I'm in construction and im finding the insolation seems to be the problem in a lot of cases, building regulations seem to change from month to month and a lot of it is with insolation. The trend seems to be locking in heat and the foil back slabs we all use today is causing to many problems, plus fitting a cavite tray on the parapet wall will stop water penetrating through your coping stones and down the inner wall.
Just came across your channel and have found lots of helpful information. I am in the process of trying to diagnose the issue with my roof. I have a shallow slope EPDM Rubber Roof with rotted decking above a bathroom and trying to figure out what is causing it. After opening up the ceiling in the bathroom, it looks like the drywall ceiling is mounted to 2x4 framing that is mounted to the joists/rafters(not sure proper name) to level off the ceiling since they are at a slight angle. It looks like there is painted wood fiberboard insulation on top of the board that used to be the exposed ceiling (It looks/feels like compressed cardboard almost?). There is OSB on top of it and I don't know what else might be between the OSB and EPDM rubber roof. In between the joists there is white fluffy like insulation (not paper, foil, or anything else on the surfaces) that seems to fill the space between the drywall and wood fiberboard insulation. I only opened a small section by the bathroom ceiling fan vent, but it looks like there is a 2x4 between the joists under the wood fiberboard insulation in one spot to help hold it up? The wood fiberboard insulation seems to have some sag where it has no support between two joists. I can see rusted nails in that 2x4, a little bit of mold on the wood fiberboard insulation, and we discovered a bunch of carpenter ants up as well as some ant waste or chewed up wood(?) there when we opened up the ceiling. I am not sure if it is a bad design, lack of vapor barrier, bad vent, or leak from the roof causing the issue of the rotted decking. Do you have any ideas?
Try cross batten to allow air cross movement before final osb board install,vents could then be fitted to side facias
Cross battening is the way to go
Another good informative video Steve👍
Thanks,
Great vid 1 question comes to mind like a cold roof does a warm roof require 50mm of ventilation?
great explanation.
god job
well done
why does one want the vapor barrier going up the sides, vs down the walls. does it matter what direction the ends of the vapor barrier go? isn't the most important thing that it is sealed at the edges?
No wonder we are having so many ventilation issues on any building works we are being led to believe seal seal seal it up well the fact is all buildings are meant to breath even cavaties in brickwork so my tutor told me ?
Excellent video just like the others, do you mind if I ask what software you are using for your models Steve? TIA
sketchup 2017
@@SteveRoofer oh really..
Awesome.! Thanks for replying Steve 😎
Loving your videos. Many thanks. I’ve now got a 16X9 timber workshop I want to fully insulate to use all year round. Can you point me in the right direction for the best approach to this? Thanks for any help. Paul.
Yes, absolutely sounds like a nice project how far have you got with it? perhaps send me some photos and info and ill see if I can help
Steve Roofer hi Steve. Thanks for the prompt response. No photos as yet. Shed is 19mm shiplap cladding on a 3x2 wall frame. I am thinking of inserting 50mm PIR boards between studs with one inch gap behind. I plan to go around the boards on the inside with foam to fill gaps. Do I need any membrane on the cold side of the boards and should I cover the walls with a vapour barrier before putting up ply facing?
The roof is wooden boarding covered with green mineral felt with an uninsulated metal profile sheet on top. The boards sit on wooden trusses. I am unsure how best to insulate the roof. Any ideas?
Thanks for any guidance.
@@SteveRoofer Hi Steve. I have tried to attach a photo of the shed but I am unable to paste it in this post - apologies. Its a standard shed construction and I want to create a heated workspace for my woodworking hobby and need to insulate walls and roof space. Having viewed your very helpful videos I am concerned about creating hidden damp spaces. I would welcome your thoughts/guidance. Many thanks.
Hi Steve, great set of videos - really useful!! A quick question related to this; if you have a mixture of a warm roof (50mm) of insulation on top of vapour barrier and osb and a cold roof 75mm of insulation between joists and a void between the two - would the void need to be vented? There are spot lights that have hooked through the 75mm of insulation that could let moisture up into the void. Many thanks in advance!
No you don't want to put more insulation in the roof van is above it generally speaking you want 3/4 of the installation outside and only 1/4 inside I have seen people do 50-50 and they do get away with it however this is all down to how are you live in the property and the relative humidity inside the room below
I hate having rock wool inbetween the drywall and wetwall. It allows water to bridge the gap. Better than pink fibreglass though. The air gap is there for a reason silly environmentalists!
Hello could you help me with some info i got a cold roof that pond badly how would i give it a slop i can tear the old roof off it like 50 yrs old
Hi Steve great video - what is the make/model of your camera you use to inspect hard to get to areas displayed in this video and do you recommend it?
Wireless Inspection Camera, Depstech Premium WiFi Borescope Endoscope 1080P HD Snake Camera for Android and IOS Smartphone, iPhone, Samsung, Tablet - Black(11.5FT)
It's good but not perfect easy as it connects to the iPhone but actually, you don't see much inside roof with it used it many times but haven't found that it's given me much get better results cutting a bigger hole and putting iPhone or GoPro down the hole
Informative video Steve, clearly a pro. We haver a similar style rear extension currently being build that requires a cold roof to avoid roof build up. We've specified web style joists and vents all round in the parapet walls to remove moist air build up. Can I ask what kind of air vents you would use please. Thanks in advance. Ernesto
Whats the solution if your coping stones are too small. Is there a way to modify or seal them
What was the final product you put down, was it a keeper system?
how is this roof floating? what is it fixed on? i used to think roof should be on top of the walls and then parapet built on top of the roof?
Hi. I have a question. Do I suppose to do a vented void (50mm) on a flat warm roof?
On my project it's 18mm playwood -> membrane -> isolation ->18mm playwood.
Without any vent gap between membrane and isolation. Is that ok ??
so basically insulating this kind of roof causes problems ergo no insulation no problem.
what material did you use to stick down the vapour barrier??
We use the primer that comes with it however contact adhesive also work
Isnt the diagram a warm roof??
It's a warm roof with a cold roof above and the cold roof above isn't vented
@@SteveRoofer I have a question about my dormer roof I have a leak but not sure where it is coming from and had some other issues to would you be able to help?
What's on the roof Steve for waterproofing originally
It was Kemper. nothing wrong with the Kemper roofing system or the way it was installed
@@SteveRoofer hate the stuff to much messing around and possibly the worst thing to get on Ur hands 😌
@@SuperMickjr Me two used to do Kemper but had to stop because of the health and safety implications
@@SteveRoofer ya from Ur men attacking u for getting another kemper job 😄