Page 80 - Glow Insulation Product Guide
P. 80

Pitched Roof: Insulated above rafters
With Quinn Therm QR
Design and Installation
Insulating a pitched roof at rafter line - to create what is usually known as a warm roof - makes full use of the building volume by making the roof space available for occupation.
Having the insulation at rafter line allows building services to be located within the insulated volume.
When installing Quinn Therm QR above the rafters on warm pitched roofs consult BS 5534 Code of practice for slating and tiling (including shingles) - Annex B for guidance on calculation methods and fixings.
To minimise the risk of interstitial condensation the roof structure should be progressively more vapour open from inside to outside.
An AVCL between the insulation and the internal finish is essential.
• QR is strong enough to span the rafters The underlay should be vapour open and to sustain loads transferred from
(vapour resistance <0.25MNs/g) but the roof covering.
water resistant, to protect against wind- driven rain and snow.
• The low thermal conductivity of Quinn Therm QR insulation boards enables the required U-value to be achieved with a minimum thickness of insulation, which, in turn, reduces the loads applied to fixings.
•The low emissivity facings increase the thermal resistance of the air space beneath the insulation, improving the overall thermal performance of the roof.
• Suitable
refurbishment projects.
for new build and
•Quinn Therm QR rigid insulation is well suited to use in warm roof constructions on new build or on refurbishment projects where the roof is to be stripped and re-covered.

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