Timber frame specialist Seven Oaks Modular Ltd was awarded the contract to
construct wall panels in their factory for
this development, followed by delivery
and installation on-site with the need to
ensure the client met the target U-value of
0.19W/m2K for the wall.
With key challenges being the requirement to reduce material waste in the factory and
to value engineer without severely impacting labour cost, Seven Oaks Modular sought the expertise of Protect Membranes to deliver an innovative solution through the use of low emissivity, reflective membranes to meet these objectives.
Following detailed technical discussions, a series of U-value calculations to meet the target 0.19W/m2K U-value was undertaken by Protect’s technical team along with a condensation risk analysis. The proposed wall type was adapted to incorporate Protect TF InterFoil, a vapour permeable, reflective membrane installed within the panel on the back of the sheathing board on the cold side of the insulation, with the foil facing into an airspace to ensure low emissivity performance.
A combination of Protect’s reflective, external breather membrane TF200 Thermo facing a 50mm unventilated cavity and the reflective, internal vapour control layer Protect VC Foil Ultra facing into a 25mm still airspace helped to create a radiant barrier.
The proposed solution was agreed by Seven Oaks Modular and resulted in enhanced thermal efficiency and reduced energy loss. The use of three reflective membranes also enabled important insulation cost savings to be made as the PIR board was able to be reduced in thickness by 40mm.
The overall total wall footprint also remained the same thereby keeping within the original specification, whilst in the factory, cost savings were made by reducing production waste. The new build-up allowed both Protect TF200 Thermo and Protect TF InterFoil to be precision fitted in the factory under controlled conditions, with Protect VC Foil Ultra fixed on-site.
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