Installation
When fitting Non-Itch, the roof structure must have provisions in place for preventing condensation. Adequate permanent ventilation of the roof space should be provided by continuous openings or frequently spaced vents of equivalent area positioned along two opposite sides of the roof at eaves level. For pitched roofs greater or less then 15 degrees, roofs with spans exceeding 10m, and mono-pitched roofs, should be in accordance with clause 9.4 (in particular 9.4.7.1) of BS 5250 : 1989. Further information and guidance is given in BRE Report No 262 Thermal insulation : avoiding risks. In roof structures incorporating the insulation at ceiling level, a breathable membrane can be used to limit excessive condensation.
Application
For safety, work from suitable “crawling boards” spanning four joists. Start from the eaves ensuring the wall plate is covered and work towards the centre of the loft, placing Non-Itch between the joists (on top of any existing insulation in place). Butt joint where necessary. When space along the joists is filled, the end of the roll can be turned back to start an extra layer of insulation or may be cut to size. Layer insulation to the required thickness ensuring the ceiling beneath is completely covered except directly under the water tank. Where the depth of previously installed insulation has reached the top of the joists, extra heat saving is gained by cross layering (at right angles to joists) with Non-Itch. Insulate and draught seal the loft hatch.
Handling and Storage
Non-Itch General Purpose Insulation Roll 42.5 is easy to handle with no protective clothing and easy to install, being lightweight and easily cut to size. Non-Itch General Purpose Insulation Roll 42.5 is supplied in polythene packaging, designed for short term protection only.
Insulation between joists
The table below shows the U-values achieved using Non-Itch laid in the roof void.
U-values are based on the first layer of insulation laid between the joists, and the remaining thickness installed as a second layer, cross-laid over the joists to reduce cold bridging.
|
Thickness of Non-Itch (mm) |
U Value (W/m2K) |
|
|
1st Layer |
2nd Layer |
|
|
100 |
170 |
0.16 |
|
100 |
200 |
0.14 |
|
150 |
200 |
0.12 |
Non Itch Roll specifications...
|
Thickness |
Width |
Length |
Area |
Thermal |
Thermal Resistance |
|
100mm |
2 x 570mm |
8m |
9.12m² |
0.0425 W/mk |
2.353 M²K/W |
|
100mm |
3 x 380mm |
8m |
9.12m² |
0.0425 W/mk |
2.353 M²K/W |
|
150mm |
2 x 570mm |
5.33m |
6.07m² |
0.0425 W/mk |
3.529 M²K/W |
|
150mm |
3 x 380mm |
5.33m |
6.07m² |
0.0425 W/mk |
3.529 M²K/W |
|
170mm |
2 x 570mm |
4.71m |
5.36m² |
0.0425 W/mk |
4.000 M²K/W |
|
170mm |
3 x 380mm |
4.71m |
5.36m² |
0.0425 W/mk |
4.000 M²K/W |
|
200mm |
2 x 570mm |
4m |
4.56m² |
0.0425 W/mk |
4.706 M²K/W |
|
200mm |
3 x 380mm |
4m |
4.56m² |
0.0425 W/mk |
4.706 M²K/W |
All Non-Itch Insulation has been tested and passed Fire Test BS 5803-4
