- Example U Value Calculation -
Typical Laing Easiform Properties
 
 
Construction Type
Element: Wall - Concrete
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
18.00
0.556
0.032
0.00
0.00
External concrete leaf
75.00
1.400
0.054
60.00
4.50
Cavity
-
-
0.180
-
-
Internal concrete leaf
75.00
1.400
0.054
60.00
4.50
Plaster, dense
16.00
0.500
0.032
60.00
0.96
Inside surface resistance
-
-
0.130
U-Value, Proportionate Area Method:
1.938 (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 Phenolic Insulation
70.00
0.028
2.500
0.00
0.00
Traditional Render
18.00
0.556
0.032
0.00
0.00
External concrete leaf
75.00
1.400
0.054
60.00
4.50
Cavity
-
-
0.180
-
-
Internal concrete leaf
75.00
1.400
0.054
60.00
4.50
Plaster, dense
16.00
0.500
0.032
60.00
0.96
Inside surface resistance
-
-
0.130
U-Value, Proportionate Area Method:
0.322 (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
300.00
15.00
Traditional Render
18.00
0.556
0.032
0.00
0.00
External concrete leaf
75.00
1.400
0.054
60.00
4.50
Cavity
-
-
0.180
-
-
Internal concrete leaf
75.00
1.400
0.054
60.00
4.50
Plaster, dense
16.00
0.500
0.032
60.00
0.96
Inside surface resistance
-
-
0.130
U-Value, Proportionate Area Method:
0.335 (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.