- Example U Value Calculation -
Typical Airey Houses
 
 
Construction Type
Element: Wall - Concrete Panels
Exposure: Normal
Internal Surface Emissivity: High
External Surface Emissivity: High
Building Use: Domestic House / Flat


Prior to WBS system application
Thickness
Thermal Conductivity
Thermal Resistance
Vapour Resistivity
Vapour Resistance
 
(mm)
(W/m²K)
(m²K/W)
(MNs/gm)
(MNs/g)
Outside surface resistance
-
-
0.040
-
-
Ship lap concrete panels
15.00
1.400
0.011
100.00
1.50
Cavity
-
-
0.180
-
-
Mineral Wool Insulation
25.00
0.040
0.625
10.00
0.25
Plasterboard
12.5
0.181
0.069
50.00
0.63
Inside surface resistance
-
-
0.130
U-Value, Proportionate Area Method:
0.948 (W/m²K)


60mm Expanded Polystyrene
Thickness
Thermal Conductivity
Thermal Resistance
Vapour Resistivity
Vapour Resistance
 
(mm)
(W/m²K)
(m²K/W)
(MNs/gm)
(MNs/g)
Outside surface resistance
-
-
0.040
-
-
WBS Polymer Cement Render
10.00
0.115
0.087
100.00
1.00
WBS EPS Insulation
60.00
0.036
1.667
0.00
0.00
Profile EPS Insulation (ave)
10.00
0.033
0.303
300.00
3.00
Ship lap concrete panels
15.00
1.400
0.011
100.00
1.50
Cavity
-
-
0.180
-
-
Mineral Wool Insulation
25.00
0.040
0.625
10.00
0.25
Plasterboard
12.5
0.181
0.069
50.00
0.63
Inside surface resistance
-
-
0.130
U-Value, Proportionate Area Method:
0.321 (W/m²K)


40mm Phenolic
Thickness
Thermal Conductivity
Thermal Resistance
Vapour Resistivity
Vapour Resistance
 
(mm)
(W/m²K)
(m²K/W)
(MNs/gm)
(MNs/g)
Outside surface resistance
-
-
0.040
-
-
WBS Polymer Cement Render
10.00
0.115
0.087
100.00
1.00
WBS Phenolic Insulation
40.00
0.023
1.739
240.00
9.60
Profile EPS Insulation (ave)
10.00
0.033
0.303
300.00
3.00
Ship lap concrete panels
15.00
1.400
0.011
100.00
1.50
Cavity
-
-
0.180
-
-
Mineral Wool Insulation
25.00
0.040
0.625
10.00
0.25
Plasterboard
12.5
0.181
0.069
50.00
0.63
Inside surface resistance
-
-
0.130
U-Value, Proportionate Area Method:
0.314 (W/m²K)



 

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Provided strictly for guidance purposes only. WBS accept no liability for errors or omissions.
For a full U-value calculation, including Condensation Risk Analysis and Temperature Profiles,
please contact WBS Technical Support on 08458 382380.