- Example U Value Calculation -
Typical Woolaway Properties
 
 
Construction Type
Element: Wall - Concrete Panel
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
-
-
Concrete panel, external
50.00
0.833
0.060
100.00
5.00
Cavity (uninsulated)
50.00
0.278
0.180
0.00
0.00
Concrete panel, internal
50.00
0.833
0.060
100.00
5.00
Dense plaster
13.00
0.500
0.026
60.00
0.78
Inside surface resistance
-
-
0.130
U-Value, Proportionate Area Method:
2.016 (W/m²K)


90mm 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
0.00
0.00
WBS EPS Insulation
90.00
0.036
2.500
0.00
0.00
Concrete panel, external
50.00
0.833
0.060
100.00
5.00
Cavity (uninsulated)
50.00
0.278
0.180
0.00
0.00
Concrete panel, internal
50.00
0.833
0.060
100.00
5.00
Dense plaster
13.00
0.500
0.026
60.00
0.78
Inside surface resistance
-
-
0.130
U-Value, Proportionate Area Method:
0.324 (W/m²K)


50mm 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
0.00
0.00
WBS Phenolic Insulation
50.00
0.021
2.381
0.00
0.00
Concrete panel, external
50.00
0.833
0.060
100.00
5.00
Cavity (uninsulated)
50.00
0.278
0.180
0.00
0.00
Concrete panel, internal
50.00
0.833
0.060
100.00
5.00
Dense plaster
13.00
0.500
0.026
60.00
0.78
Inside surface resistance
-
-
0.130
U-Value, Proportionate Area Method:
0.349 (W/m²K)



 

Line Break

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.