- Example U Value Calculation -
Typical No-Fines Property
 
 
Construction Type
Element: Wall - Concrete, No Fines
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
-
-
Traditional Render
25.00
0.556
0.045
0.00
0.00
No Fines, concrete
225.00
1.402
0.160
60.00
13.50
Plaster, dense
15.00
0.500
0.030
60.00
0.90
Inside surface resistance
-
-
0.130
U-Value, Proportionate Area Method:
2.494 (W/m²K)


70mm PIR
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 PIR Insulation
70.00
0.028
2.500
0.00
0.00
Traditional Render
25.00
0.556
0.045
0.00
0.00
No Fines, concrete
225.00
1.402
0.160
60.00
13.50
Plaster, dense
15.00
0.500
0.030
60.00
0.90
Inside surface resistance
-
-
0.130
U-Value, Proportionate Area Method:
0.335 (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
Traditional Render
25.00
0.556
0.045
0.00
0.00
No Fines, concrete
225.00
1.402
0.160
60.00
13.50
Plaster, dense
15.00
0.500
0.030
60.00
0.90
Inside surface resistance
-
-
0.130
U-Value, Proportionate Area Method:
0.349 (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.