Mon, 25 May 2026 17:56:37 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9170#Comment_9170 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9170#Comment_9170 Fri, 09 Nov 2007 18:26:15 +0000 snowy1988 snowy1988]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9172#Comment_9172 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9172#Comment_9172 Fri, 09 Nov 2007 18:32:42 +0000 tony
The roof will now have to a cold deck roof so how deep are the bits of wood?

My ideal and cheapest would be 300mm of quilted insulation with a 50mm ventilated air gap between it and the deck.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9175#Comment_9175 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9175#Comment_9175 Fri, 09 Nov 2007 18:54:07 +0000 snowy1988 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9176#Comment_9176 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9176#Comment_9176 Fri, 09 Nov 2007 19:06:23 +0000 steveleigh
If it is above heated accommodation my advise is don't pay them and get your local building inspector involved. They maybe liable for not advising you about the building regulation requirement PART L1 B 2006.
Your room will always be colder than it should be due to the failure of this roofing company. Moisture will be attracted to the cold deck and will condense and in a few years you'll end up with a rotten roof.

Tony is right but is it feasible at this point to provide a 50mm through ventilated air gap? Also you'll probably struggle to get enough insulation between the joists to meet building regulations. It depends how deep the joists are. Another option is an inverted roof (insulation on top of the membrane) but allow an extra 50% thickness in insulation for heat loss because of water infiltration and you'll need 2 inch paving slabs on top of the insulation with lead flasihing on the ends. You would have an increased loading on your roof.

My company install flat roofs and always advise a warm-deck roof above heated accommodation because we would liable for the situation you are in.

I always check with insulation suppliers technical department for latest advice to meet building regulations and pass this information on to the customer. All this information should be given to you pre sale.

There is also a possibility that the roof could be raised in a survey for not meeting building regulations. Cold roofs are banned in Scotland.

Cheers

Steve]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9177#Comment_9177 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9177#Comment_9177 Fri, 09 Nov 2007 19:37:08 +0000 Saint Two ways to keep the insulation in position. One if the roof can take the load then its simply ballasted to the same thickness as the insulation boards themselves. two if the roof cannot take the load then go for a lightweight solution which has the extruded polystyrene with hT&G jointing rather than shiplap with a 10mm modified cement screed on it. This can be secured in place by adhesion or just loading the perimeter boards with paving slabs 450 x 450 x 50 will do but check prevailing wind. Suppliers won't sell the products unless the know the height, orientation and shape of your roof.There are a few suppliers of XPS for USD roofs, try Dow Styrofoam Roofmate, Knauf Roofboard, can't remember the Kingspan one but its probably based on BASF's Styrodur if its a green foam, otherwise its Styrofoam, Ursa XPS or similar.
For the lightweight varieties there is Dow's Roofmate LG and Styrodur's Chevron, now marketed by Kingspan.

Look upon this as an opportunity not a problem. I did one of these on my house a few years back and it worked fantastically]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9178#Comment_9178 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9178#Comment_9178 Fri, 09 Nov 2007 19:49:40 +0000 Mike George
Can I ask if the roof is ventilated in any way? This is the Critical point in deciding which will be the most effective [and cheapest] way forward.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9186#Comment_9186 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9186#Comment_9186 Fri, 09 Nov 2007 21:35:53 +0000 snowy1988 The roof is not ventilated. Building Control will see the roof anyway because they will be inspecting other work we are doing. The problem arose because we were referred to this contractor by a Firestone rep who sent our architect information about the warm roof system. We thought this was what we were getting but it has turned out the quote was only for supply and fit of the EPDM.
Snowy]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9189#Comment_9189 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9189#Comment_9189 Fri, 09 Nov 2007 22:08:37 +0000 Mike George http://www.delston.co.uk/epdm.htm

If so, can it be rolled up and relaid on top of a newly insulated deck? This would then be in accordance with the practice outlined at delston above. Otherwise Saint's suggestion may be the cheapest and best way to go. Mike]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9236#Comment_9236 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9236#Comment_9236 Sun, 11 Nov 2007 17:26:23 +0000 adrian hollister
My key concerns at this stage are: planning (as all options seem to change the height of the roof; skills (there is only me to do this so anything requiring specialist skills is out); and insulation/water proofing. Thoughts?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9240#Comment_9240 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9240#Comment_9240 Sun, 11 Nov 2007 18:03:10 +0000 Mike George http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=632&page=1#Item_10]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9248#Comment_9248 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9248#Comment_9248 Sun, 11 Nov 2007 21:02:10 +0000 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9249#Comment_9249 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9249#Comment_9249 Sun, 11 Nov 2007 21:16:30 +0000 adrian hollister https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9257#Comment_9257 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9257#Comment_9257 Sun, 11 Nov 2007 22:35:30 +0000 Mike George Posted By: tonyAdrian, how will you join up your roof insulation to that in or on the walls? You may finish up with massive thermal bridging negating the insulation that you do.

Isn't that a bit of an exageration? Surely insulating the flat roof is a great idea regardless of any thermal bridging.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9258#Comment_9258 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=851&Focus=9258#Comment_9258 Sun, 11 Nov 2007 23:41:22 +0000 tony
Roof could be as simple as eps on top of what is there then boards fixed then waterproofing layer.

I once saw a waterproofing layer of one layer of cheapest black felt not stuck down or fixed with 25mm of stones in it never leaked for 60 yrs. fall was 1 in 35]]>