Page 79 - Glow Insulation Product Guide

PIR (PITCHED ROOF)
1 - Quinn Therm QR boards between rafters & supported by battens
2 - Quinn Therm QR boards over rafters 3 - Stop batten
4 - Counterbattens
5 - Vapour open underlay
6 - Roof covering
U-value results below based upon pitched roof construction shown:
6
5 4
2
1
3
150mm deep rafters @400mm centres;
Quinn Therm QR between rafters; Quinn
Therm QR above rafters; vapour open underlay; 50mm cavity formed by counterbattens; large format concrete tiles. Calculations performed to
BS EN ISO 6946, taking account of repeating thermal bridges.
Required thickness of Quinn Therm QR
Insulation between rafters
Insulation above rafters (mm)
60 70 80 90 100 110 120 125
thickness (mm)
50 60 70 80 90
100 110 120
U-value (W/m 2K)
0.20 0.18 0.19 0.17
- 0.16
- -
- -
- -
- -
- -
0.17 0.16 0.16 0.15 0.15 0.14 0.14 0.13 - 0.13
0.15 0.14 0.13 0.13 0.14 0.13 0.13 0.12 0.13 0.12 0.12 0.12 0.13 0.12 0.11 0.11 0.12 0.11 0.11 0.11 0.12 0.11 0.11 0.10
- -
--- 0.11 0.10 0.10 - - - - 0.10 0.10
Note: the thickness of the insulation above the rafters must be equal or greater than the thickness of insulation between the rafters.
Design and Installation
At eaves, wall insulation should be continued between the rafters until it butts the underside of the Quinn Therm QR boards. Where there is a cavity closer at the wall head the additional wall insulation may be fixed to the wall plate.
Gable walls should be insulated for their full height and the insulation extended to meet the underside of the Quinn Therm QR boards.
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