Page 81 - Glow Insulation Product Guide

PIR (PITCHED ROOF)
1 - Quinn Therm QR boards 2 - Quinn Therm QR boards 3 - Stop batten
4 - Counterbattens
5 - Vapour open underlay 6 - Roof covering
U-value results below based upon pitched roof construction shown:
150mm deep rafters @400mm centres;
Quinn Therm QR; vapour open underlay;
38mm 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
Design and Installation
6
3
5
4
1
2
Quinn Therm QR insulation (mm)
100 110 120 125 130 140 150
U-value (W/m 2K) 0.19 0.17 0.16 0.16 0.15 0.14 0.13
To limit heat loss and prevent problems such as condensation, mould growth and staining occurring at cold spots in the construction, insulation should be continuous at junctions between the roof and other elements, particularly the eaves and gable.
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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