Tue, 19 Dec 2023 08:33:40 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301365#Comment_301365 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301365#Comment_301365 Thu, 27 Apr 2023 08:32:58 +0100 kaicasswell
Ground temps at that depths are pretty constant so it seems I don’t need as much as a normal ground floor?
The architects just put 150mm but that seems excessive.
Please and thank you!]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301366#Comment_301366 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301366#Comment_301366 Thu, 27 Apr 2023 08:58:38 +0100 Peter_in_Hungary http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301367#Comment_301367 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301367#Comment_301367 Thu, 27 Apr 2023 10:00:21 +0100 fostertom http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301368#Comment_301368 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301368#Comment_301368 Thu, 27 Apr 2023 10:47:35 +0100 WillInAberdeen
So every 1m thickness of soil is equivalent to 20-40 mm of insulation.

If you think of the basement floor as equivalent to a normal ground floor, but with 3m of extra soil thickness piled up all round the outside, that's like having (3x20 to 3x40) = 60-120 mm of extra insulation value from the extra depth of soil, in addition to the usual soil insulation value beneath a ground floor.

You'd probably still want a bit more than that in a normal ground floor, maybe add another 100mm underneath the basement floor? Won't cost much in the scheme of things, compared to digging the hole and pouring the concrete.

Need more than that in the basement walls because there is less than 3m path of soil from them to the outside ground level.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301370#Comment_301370 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301370#Comment_301370 Thu, 27 Apr 2023 14:53:32 +0100 fostertom a) that path length increases, and thus equiv insulation thickness, against losses from points closer to the middle of the floor;
b) the 'given' temp gradient in the subsoil, from 3m depth up to surface, will be only 10K or less, instead of 21K thro a wall, thus that 60-120 will be worth 120-240.

So raw winter floor heat loss may be a little greater than with say 150-300 of wall woodfibre; that is to be balanced against the advantage of a massive block of year-round temp stability within the thermal envelope.

This does depend upon really good insulation to the basement walls, as a 'coffer dam' of insulation with very little loss/leakage thro it, to force that path length that heat loss has to take to the surface.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301371#Comment_301371 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301371#Comment_301371 Thu, 27 Apr 2023 14:54:34 +0100 tony
I did put 25mm of EPS under a floating floor. I have an interseasonal thermal store under the house which changes the approach]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301372#Comment_301372 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301372#Comment_301372 Thu, 27 Apr 2023 14:58:55 +0100 fostertom
Your interseasonal cold store is just an augmented/mechanised/not so 'passive' version of what I've proposed.

No tanking because what? french drain guaranteeing unsaturated ground hence zero hydrostatic pressure?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301373#Comment_301373 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17824&Focus=301373#Comment_301373 Thu, 27 Apr 2023 17:09:18 +0100 kaicasswell I’ll ask my building control officer what I can get away with. Maybe…..]]>