Glidevale has launched a roof insulation system which it says can help achieve a 20% improvement in thermal performance while still limiting risk of condensation build-up in the roof.
Under BS 5250:2002 Amendment 1 2005, inclusion of a low-resistance vapour-permeable roof underlay with a well-sealed ceiling and a separate vapour control layer on the warm side of the insulation eliminates the need to include roofspace ventilation.
Glidevale’s strategy focuses on its Protect VP400 high-performance vapour-permeable roof underlay, and Protect VC Foil reflective low-emissivity vapour control layer. It says Protect VC Foil can reduce conventional insulation requirements by over 15%, and has also shown thermal performance improvements to 0.16W/m2K – in conjunction with suitable insulation. Depending on the detailing, the system can also reduce thermal bridging through the rafters.
Protect VP400 underlay is highly vapour-permeable but entirely watertight and ensures moisture build-up in the roof is efficiently transferred through the roof covering, eliminating the need for additional ventilation in the roof in a warm roof configuration. It acts as a secondary line of defence against any wind-driven rain or snow. Its UV resistance and watertightness allows its use as a temporary roof covering for up to three months.