Green Building Forum - Solid floor Uvalue calculation Mon, 25 May 2026 22:10:34 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Solid floor Uvalue calculation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8403&Focus=129717#Comment_129717 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8403&Focus=129717#Comment_129717 Thu, 12 Jan 2012 16:12:15 +0000 kilmo exposed permitter (m) divided by floor area m2 = unisulated floor uvalue?

and the "exposed" is just the area on the outside walls?]]> Solid floor Uvalue calculation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8403&Focus=129728#Comment_129728 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8403&Focus=129728#Comment_129728 Thu, 12 Jan 2012 16:41:49 +0000 kilmo yellow line, is the perimeter 13m

so p/a ratio is 0.38

correct?

whats the uvalue?]]> Solid floor Uvalue calculation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8403&Focus=129742#Comment_129742 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8403&Focus=129742#Comment_129742 Thu, 12 Jan 2012 17:21:43 +0000 Nick Parsons Solid floor Uvalue calculation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8403&Focus=129798#Comment_129798 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8403&Focus=129798#Comment_129798 Fri, 13 Jan 2012 07:56:46 +0000 CWatters http://www.warmafloor.co.uk/knowledge-center/catagories/insulation.asp

Quote:

A simplified method of calculating the U-Value of an uninsulated floor has been described in BRE Information Paper IP 3/90.

The IP 3/90 formula is:

U = 0.05 + 1.65(P/A) - 0.6(P/A)²

Where:

U = U-Value of the uninsulated floor (W/m²K).

P = Length of the exposed perimeter (m).

A = Area of the floor (m²)]]> Solid floor Uvalue calculation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8403&Focus=129811#Comment_129811 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8403&Focus=129811#Comment_129811 Fri, 13 Jan 2012 08:47:16 +0000 tony Solid floor Uvalue calculation https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8403&Focus=129885#Comment_129885 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8403&Focus=129885#Comment_129885 Fri, 13 Jan 2012 13:15:23 +0000 kilmo
so for my above floor with a p/a ratio of 0.38
U = 0.05+1.65 0.38-0.6 0.38^2
u =0.59036W/m²]]>