National design handbook prototype on passive solar heating and natural cooling of buildings 
Uvalues for solid floors in contract with the earth with tour exposed edges
Dimensions of floor 
Uvalue (W/mN.degC) 
Very long x 30m broad 
0.16* 
Very long x 15m 
0.28* 
Very long x 7.5m 
0.48* 
150m x 60m 
0.11 
150m x 30m 
0.18 
60m x 60m 
0.15 
60m x 30m 
0.21 
60m x 15m 
0.32 
30m x 30rn 
0.26 
30m x 1 Sm 
0.36 
30m x 7.5m 
0.55 
15m x 15m 
0.45 
15m x 7.5rn 
0.62 
7.5m x 7.5m 
0.76 
3m x 3m 
1.47 
* This value applies also for any floor of this breadth and losing heat from two parallel edges. (Breadth here is the distance between exposed edges.)
Corrections to the above values for edge insulation floors
Dimensions of floor 
Percentage reduction in Uvalue for edge Insulation extending to a depth (m) 

0.25 
0.5 
1.0 

Very long x 150m 
2 
6 
10 
Very long x 60m 
2 
6 
11 
Very long x 30m 
3 
7 
11 
Very long x 30m 
3 
8 
13 
Very long x 6m 
4 
9 
15 
Very long x 2m 
6 
15 
25 
150m x 150m 
3 
10 
15 
60m x 60m 
4 
11 
17 
30m x 30m 
4 
12 
18 
15mx 15m 
5 
12 
20 
6mx6m 
6 
15 
25 
2mx2m 
10 
10 
35 
Basic thermal resistance values for suspended floors directly above ground
Actual floor dimension Thermal resistance 1/ft + Rair + Re (m².°C/W)
Very long x 30m broad 
5.3 
Very long x 15m 
2.8 
Very long x 7.5m 
1.7 
150m x 60m 
7.1 
150m x 30m 
4.6 
60m x 60m 
5.9 
60m x 30m 
4.0 
60m x 15m 
2.5 
30m x 30m 
3.4 
30m x 15m 
2.3 
30m x 7.5m 
1.6 
15rn x 15m 
2.0 
15rn x 7.5m 
1.4 
7.5m x 7.5m 
1.3 
3m x 3m 
0.8 
The Uvalue of suspended floors can be estimated from this table where height above ground is not greater than approximately 1.5m and ventilation is limited. (The literature gives ventilation as 2000mm² per 1000mm of perimeter.)
1/fi = inside surface resistance
Rair = air space resistance vented as specified above
Re = resistance of the earth
Refer to table above for suspended floors. Source: IHVE Guide 1977A3