andyscotland Posted June 10, 2019 Share Posted June 10, 2019 For my garage conversion / extension I'll be laying a GRP flat roof covering (on new OSB). One of the products I'm looking at (from a supplier previously recommended to me) has a 20 year manufacturer's guarantee, and a third-party fire test certificate - but it doesn't have a BBA (or other third-party) certification. My approved warrant documents don't specify it has to be BBA, and I don't have a structural warranty so no requirements there. The supplier has advised that the only thing Building Control will want to see is the fire rating document, and I shouldn't have any problems (practical or paperwork) using their system. Does that sound right - am I safe enough to go with that product? Or would I be better using a BBA system (which appear to be more limited in choice, and more expensive)? Thanks, Andrew Link to comment Share on other sites More sharing options...
nod Posted June 10, 2019 Share Posted June 10, 2019 I have a Build warranty on ours They excluded our flat roof from it as it Came with 25 years guarantee and the same period for product They wanted a insurance backed warranty That an insurance company asking for another company to insurer the liability in my opinion it’s not important If you where to sell at some stage Yiy could buy an indemnity Link to comment Share on other sites More sharing options...
Jeremy Harris Posted June 10, 2019 Share Posted June 10, 2019 Given that the cladding on Grenfell Tower had a BBA certification as being resistant to the spread of fire, then I'd have to say that it's probably not worth the paper it's written on for some products. 2 1 Link to comment Share on other sites More sharing options...
lizzie Posted June 10, 2019 Share Posted June 10, 2019 Its a minefield! We have flattish roof +250sqm our covering has BBA cert and the 20 odd year guarantee. We also have a Premier Guarantee 10 year warranty in case we want to sell...we are old may need a care home in less than 10 years LOL There is no right answer to your question sorry, your choice. Link to comment Share on other sites More sharing options...
Mr Punter Posted June 10, 2019 Share Posted June 10, 2019 In your case @andyscotland if as long as building control are OK then it is fine. Make sure the fall is adequate and the ventilation requirements are met if it is a cold roof. Link to comment Share on other sites More sharing options...
andyscotland Posted June 10, 2019 Author Share Posted June 10, 2019 Thanks all, helpful comments. It's only a fairly small area (30sqm) relative to the rest of the house and we do not expect to sell. It's a warm roof, and actually low pitched rather than flat (around 8 - 10 degrees) so no issues with fall. 2 minutes ago, Mr Punter said: In your case @andyscotland if as long as building control are OK then it is fine. Unfortunately building control have to date refused to engage with the project at all - don't want to hear from me until I'm ready for completion certificate and on a couple of things I've attempted to confirm their approval of ahead of time they won't say any more than it's for me to ensure that I can demonstrate at completion it complies with the regs.... I guess basically I just want reassurance that if I put a non-BBA-but-fire-certified product on there the building control inspector won't make me replace it at completion... Link to comment Share on other sites More sharing options...
Mr Punter Posted June 10, 2019 Share Posted June 10, 2019 I don't know if it is different in Scotland but with building control we have the option of either a full plans submission, where sure you would submit plans including the roof covering specification or a building notice which is for smaller works where you know they will comply. In your case I would do full plans and would expect an approval or a conditional approval, where they list stuff that is non-compliant or more detail required. Once you have the plan approval, as long as you do what is on the plans you are fine. Link to comment Share on other sites More sharing options...
Big Neil Posted June 10, 2019 Share Posted June 10, 2019 slight segway, and it may seem an obvious thing to ask, but can someone please give a succinct explanation of the difference between a 'warm' and a 'cold' roof. Just so I can align my understanding with what it is. Link to comment Share on other sites More sharing options...
andyscotland Posted June 10, 2019 Author Share Posted June 10, 2019 I did a full plans submission, but the (approved) spec just says the GRP system and substrate needs to meet fire rating AC or better. I didn't mention a particular manufacturer or anything more specific, though there is a general line at the beginning that all works and materials to comply with relevant BS and EN standards. So I could assume that if they wanted to require BBA that would have been flagged already - but just a little cautious as my council (who will be inspecting) are known for being stricter than the council they subcontracted my warrant application to. Link to comment Share on other sites More sharing options...
andyscotland Posted June 10, 2019 Author Share Posted June 10, 2019 2 minutes ago, Big Neil said: slight segway, and it may seem an obvious thing to ask, but can someone please give a succinct explanation of the difference between a 'warm' and a 'cold' roof. Just so I can align my understanding with what it is. A warm roof has the vapour control and insulation on top, hard up against the covering. So the rafters etc are "warm" as they're inside the heated space. A cold roof has the insulation between/below rafters and requires ventilation below the roof covering to prevent condensation. Link to comment Share on other sites More sharing options...
Mr Punter Posted June 10, 2019 Share Posted June 10, 2019 2 minutes ago, Big Neil said: slight segway, and it may seem an obvious thing to ask, but can someone please give a succinct explanation of the difference between a 'warm' and a 'cold' roof. Just so I can align my understanding with what it is. Warm roof = insulation above structure and no need to ventilate as all structure is warm Cold roof = insulation within structure and underside of roof deck needs ventilation. Link to comment Share on other sites More sharing options...
ADLIan Posted June 10, 2019 Share Posted June 10, 2019 Building Control will probably look at U-value and fire performance of external roof finish - this later requriement is down to building height and proximity to local buildings, etc. Note that Scot Regs strongly advise aginst use of cold flat roofs as do relevant British Standards Link to comment Share on other sites More sharing options...
andyscotland Posted June 10, 2019 Author Share Posted June 10, 2019 Thanks - yes, u values and fire are all ok and it's a warm roof. Link to comment Share on other sites More sharing options...
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