Mon, 25 May 2026 08:50:34 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304399#Comment_304399 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304399#Comment_304399 Sun, 26 Nov 2023 13:02:49 +0000 Victorianeco
Also any brands preferred? I'm looking to put a few of my team on a flat roofing course but as with most things they are 'product specific' to ensure warranties are met.

Would you also try to eliminate flat roofs where possible or do they serve a purpose?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304400#Comment_304400 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304400#Comment_304400 Sun, 26 Nov 2023 13:30:45 +0000 djh https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304401#Comment_304401 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304401#Comment_304401 Sun, 26 Nov 2023 13:47:21 +0000 Rex
Also used on my warm roof balconies over which I 'floated' some roof tiles (that is because my roof tiles are from NuLok and are virtually flat on the underside.)]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304402#Comment_304402 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304402#Comment_304402 Sun, 26 Nov 2023 18:51:09 +0000 revor Posted By: VictorianecoWould you also try to eliminate flat roofs where possible or do they serve a purpose?

I would not entertain a flat roof in this country. Yes they have a purpose lets you have a roof where you could not have a pitched one. Never had a property with a flat roof but my parents, my sister and a cousin have, 2 were on new properties, and both failed within 5 years necessitating complete reroof. NHBC Insurance would not cover them as flat roofs are classed as cladding and do not come under the scope of HHBC warranty. Both roofs were not done to building regs. EPDM I understand is one of the best materials but was told a few years ago that the material can suffer from pin holes and lead to problems. I have used narrow width rolls to seal in window frames it is easy to work with and the gun applied bitumen adhesive I was also impressed with.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304403#Comment_304403 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304403#Comment_304403 Sun, 26 Nov 2023 19:19:27 +0000 tony
If pushed my order of preference would be from top covering downwards, lead, asphalt, high performance felt, then the rest]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304404#Comment_304404 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304404#Comment_304404 Sun, 26 Nov 2023 19:47:53 +0000 Mike1
My top 2 would be asphalt, then high performance felt, though lead is certainly good in the right circumstances. However the detailing and the standard of installation is doubtless more important than the system chosen.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304405#Comment_304405 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304405#Comment_304405 Sun, 26 Nov 2023 20:14:24 +0000 djh
I gather Firestone is well-known and one of the better brands.

I don't think there's anything wrong with flat roofs as long as the falls are correct as already mentioned and the drains are thought about. If it was more sunny here, I'd think about putting chippings or paving slabs or somesuch on top of the rubber to keep the sun off; or have engineered the structure so I could put a green roof on top.

I wouldn't want felt or ashphalt etc. And lead is an invitation to thieves around here. As I said, I think the alternatives are GRP or TPO. Each to their own I suppose, and don't buy a house and hope to rely on the NHBC ]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304406#Comment_304406 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304406#Comment_304406 Mon, 27 Nov 2023 13:56:24 +0000 Doubting_Thomas Posted By: VictorianecoWhat is the go-to reference for flat roof coverings in 2023 onwards?

BS 6229 (2018) is the best reference material for guidance on minimum falls etc.

I wonder if you meant 'preference' though? Have you considered inverted? You need taller parapets but it allows for a potential outside area for amenity and/or PV.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304408#Comment_304408 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304408#Comment_304408 Mon, 27 Nov 2023 16:24:16 +0000 Victorianeco
Thanks]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304409#Comment_304409 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304409#Comment_304409 Mon, 27 Nov 2023 17:22:53 +0000 djh Posted By: VictorianecoParapets would be good but again, what materials would be best suited such purpose?You mean for the parapets? Ours are timber, covered in EPDM with an aluminium flashing on top.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304410#Comment_304410 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304410#Comment_304410 Tue, 28 Nov 2023 11:40:30 +0000 owlman Because of a project I'm involved with I'm curious about flat roof parapets.
You mentioned yours are aluminium I'm assuming they are right on the edge with a fascia extending down the wall. If so approx. how much down the wall does it go, I guess it overhangs the wall, by how much, does driving rain drip from it? If this is the case does it affect the wall e.g. staining?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304412#Comment_304412 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304412#Comment_304412 Tue, 28 Nov 2023 15:59:03 +0000 borpin
I think no matter what, it is down to how well it is constructed. There is more room for error with a flat roof.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304413#Comment_304413 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304413#Comment_304413 Tue, 28 Nov 2023 16:47:54 +0000 djh Posted By: owlmanYou mentioned yours are aluminiumNo, I said they were timber. With an aluminium flashing cap.

I've never looked to see what happens when there's driving rain. We haven't seen any problems. I assume water falling on the parapet drips or runs off it, apart from what little evaporates. Just as the water falling anywhere else does.

I like sedum flat roofs too. Was just too busy to think about them when building. ]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304414#Comment_304414 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304414#Comment_304414 Tue, 28 Nov 2023 18:07:35 +0000 owlman https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304415#Comment_304415 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304415#Comment_304415 Tue, 28 Nov 2023 20:24:44 +0000 djh https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304423#Comment_304423 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304423#Comment_304423 Thu, 30 Nov 2023 10:22:22 +0000 djh https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304424#Comment_304424 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304424#Comment_304424 Thu, 30 Nov 2023 11:55:34 +0000 owlman My situation is also horizontally boarded with an aluminium clad parapet on a flat roof. I was primarily concerned about rain runoff from the fascia bit onto the timber under and below potentially creating problems. I think with a bit of detailing like sloping the aluminium top, inwards onto the flat roof, and keeping the exterior down stand e.g. 150-200 max. don't know yet about any exterior drip detail on the aluminium bottom edge, I'm guessing just a upturn towards the wall. Have to see how the aesthetic looks.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304486#Comment_304486 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304486#Comment_304486 Tue, 05 Dec 2023 09:55:48 +0000 borpin
I've used this tape in numerous places and it does a great job at sealing things.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304490#Comment_304490 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304490#Comment_304490 Tue, 05 Dec 2023 12:20:58 +0000 djh Posted By: borpinThe other thing to consider is ventilation; is the gap between the timber cladding and the fascia down stand bit needed for that. If not, have a small under turn on it and when fitting put some expanding EDPM foam tape between it and the timber.I'm not sure I understand. What gap? The aluminium flashing is formed down over the timber cladding, so there's no ventilation gap as such although I expect liquid water could run down if it needed to. And what benefit would be gained by sealing that space anyway?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304510#Comment_304510 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304510#Comment_304510 Wed, 06 Dec 2023 13:54:06 +0000 borpin Posted By: djhI'm not sure I understand.It was more a question for owlman.

Where the aluminium comes down over the wooden cladding, unless fixed hard with sealant against it, there would be a natural gap (might only be a couple of mm) but 2 different materials in contact would not be naturally 'sealed'.

If the cladding is on battens, the design might allow for ventilation and the gap at the top being part of that ventilation.

Depending on aspect and location, there might be a risk of driven rain getting up under the aluminium between it and the cladding and that might be undesireable.

If there is a gap that needs sealing, one solution (I hate Silicon) is to use thin expanding foam tape to provide a weatherproof seal.

Where the aluminium comes down and stops, is there a small underfold as a finishing or just a plain end (powder coated surface?)]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304516#Comment_304516 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304516#Comment_304516 Wed, 06 Dec 2023 17:04:54 +0000 djh
Certainly I can't see any great difference between the cladding up top and that lower down. But then we don't live in an area of extreme weather, so things might differ depending on where a building is.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304727#Comment_304727 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=304727#Comment_304727 Sun, 24 Dec 2023 02:27:17 +0000 wookey But I think a GRP roof can also be good, and can be DIYed.
I got Sarnafil because that's what the roofers were certified for and used to. I don't think there is any performance difference between between EPDM and PVC membranes, but the EPDM is less environmentally harmful to manufacture.

I have DIYed EPDM on sheds and it's great. Many times better than classic roofing felt - I will never use that stuff again. A sufficiently complicated roof will need on-site welding and that needs professionals (or at least their tools and some appetite for risk).]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=305028#Comment_305028 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=305028#Comment_305028 Sat, 20 Jan 2024 22:33:01 +0000 Victorianeco
The existing osb and felt is shot so I was wondering about doing away with the osb and felt and just using sheets?

I've also wondered, how does one fill the gaps at the end of the sheets to make them watertight?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=305029#Comment_305029 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18038&Focus=305029#Comment_305029 Sat, 20 Jan 2024 22:50:34 +0000 tony