Green Building Forum - Another Floor Insulation Question Wed, 10 Jun 2026 09:32:31 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Another Floor Insulation Question https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53384#Comment_53384 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53384#Comment_53384 Tue, 05 May 2009 13:34:14 +0100 mitchino Another Floor Insulation Question https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53386#Comment_53386 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53386#Comment_53386 Tue, 05 May 2009 14:32:22 +0100 sinnerboy
http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,1642,en.pdf

See diagram 7 on page 18 - the detailing is all about keeping the suspended timber well clear of the concrete sub floor below - the void below must be vented .

Your timbers are lying directly on the concrete subfloor ? I would not place any insulation here for fear of causing condensation which will lead to rotting of your structural floor timbers .

Is placing a 75mm dense insulation + 75mm screed over an option for you ? ( after stripping all joists out )]]> Another Floor Insulation Question https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53390#Comment_53390 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53390#Comment_53390 Tue, 05 May 2009 15:36:31 +0100 mitchino
I remember labouring for my builder brother when he converted our barn a few years back - if memory serves he dug out the earth floors, put down compressed type 1, with sand on top, laid damp proof sheeting on that, then a concrete pour, then battened the floor with kingspan between the joists and floorboards over that. Everything was passed by building control.]]> Another Floor Insulation Question https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53391#Comment_53391 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53391#Comment_53391 Tue, 05 May 2009 15:37:53 +0100 mitchino
http://www.insulation.kingspan.com/uk/pdf/k3.pdf]]> Another Floor Insulation Question https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53394#Comment_53394 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53394#Comment_53394 Tue, 05 May 2009 16:53:23 +0100 sinnerboy
If you introduce insulation now - the concrete will be thermally separated from the internal space . It will get cold
Condensation will tend to arise more frequently and in greater amounts . The insulation being vapor resistant will leave only the timbers to cope .

I would ask Kingspan for a project specific condensation risk analysis - sent to you in pfd format - before relying on the detail link above]]> Another Floor Insulation Question https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53398#Comment_53398 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53398#Comment_53398 Tue, 05 May 2009 18:01:28 +0100 mitchino Another Floor Insulation Question https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53423#Comment_53423 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53423#Comment_53423 Tue, 05 May 2009 21:08:13 +0100 sinnerboy
http://www.vencel.co.uk/assets/bba/1796_web.pdf]]> Another Floor Insulation Question https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53463#Comment_53463 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53463#Comment_53463 Wed, 06 May 2009 09:21:20 +0100 mitchino Another Floor Insulation Question https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53538#Comment_53538 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53538#Comment_53538 Wed, 06 May 2009 18:11:42 +0100 mark_s
existing situation is a earth sub floor. I am intending a layer of hardcore, then a layer of geotex or similar. Sand blinding then dpm. Then insulation. On top of the insulation a layer of ply with battens which will support the floorboards.
I intend that the water and electricity pipes will run between the battens and then I'll stick in rockwool type stuff.]]> Another Floor Insulation Question https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53539#Comment_53539 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3972&Focus=53539#Comment_53539 Wed, 06 May 2009 18:12:38 +0100 mark_s