Table 18 Vapour Resistivities
|
Material
|
Resistivity
|
|
|
Typical
|
Range
|
|
|
(GN s/kg m)
|
(GN s/kg m)
|
|
|
|
|
|
Asbestos Cement Sheeting and Substitutes:
|
300
|
200 - 1000
|
|
|
|
|
|
Blockwork and Brickwork:
|
|
|
|
Lightweight / aerated blocks
|
30
|
20 - 50
|
|
Medium weight blocks
|
50
|
30 - 80
|
|
Dense / clinker blocks
|
100
|
60 - 150
|
|
Common / facing brick
|
50
|
25 - 100
|
|
Sandlime / engineering brick
|
100
|
80 - 250
|
|
|
|
|
|
Boards etc.:
|
|
|
|
Cork board
|
100
|
50 - 200
|
|
Chipboard
|
500
|
|
|
Fibreboard - Plain or tile
|
40
|
15 - 60
|
|
Hardboard
|
600
|
450 - 1000
|
|
|
|
|
|
Carpeting:
|
|
|
|
Normal backing
|
10
|
7.0 - 20.0
|
|
Foam backed or with underlay
|
200
|
100 - 300
|
|
|
|
|
|
Concrete (cast):
|
|
|
|
Lightweight / aerated
|
40
|
30 - 80
|
|
Medium weight
|
100
|
60 - 150
|
|
Dense
|
200
|
|
|
No fines
|
20
|
|
|
|
|
|
|
Insulating Materials:
|
|
|
|
Polystyrene - expanded bead
|
300
|
100 - 600
|
|
- expanded extruded
|
1000
|
600 - 1300
|
|
Polyurethane foam (closed cell)
|
600
|
500 - 1000
|
|
Glass fibre
|
7
|
|
|
Expanded or foamed glass
|
10000
|
|
|
Urea formaldehyde
|
15
|
10.0 - 30.0
|
|
Vermiculite
|
15
|
|
|
PVC sheet or tile
|
1000
|
800 - 1300
|
|
|
|
|
|
Plaster:
|
|
|
|
Plaster
|
60
|
|
|
Plasterboard
|
60
|
|
|
|
|
|
|
Screeds and Renders:
|
|
|
|
Rendering
|
100
|
|
|
Screed
|
100
|
|
|
|
|
|
|
Stonework:
|
|
|
|
Granite, slate and marble
|
300
|
150 - 450
|
|
Limestone and sandstone
|
200
|
150 - 450
|
|
|
|
|
|
Tiles:
|
|
|
|
Roofing tile or slating
|
250
|
50 - 300
|
|
Ceramic tiling
|
2000
|
500 - 5000
|
|
|
|
|
|
Timber:
|
|
|
|
General
|
60
|
40 - 70
|
|
Pine
|
500
|
|
|
Plywood
|
1000
|
150 - 6000
|
|
Woodwool slabs
|
20
|
15 - 40
|
Source of data: BSI 5250
