NBT envelope succeeds at Expo

Natural Building Technologies’ (NBT’s) woodfibre insulation systems have demonstrated their high performance with the insulation of a detached, timber frame new build house designed by Malcolm Fraser Architects for Scotland’s Housing Expo. Creating a highly insulated, airtight building envelope, NBT’s Pavaroof and Pavaclad woodfibre insulation systems enabled the architects to deliver an optimally comfortable living environment with a predicted annual running cost of just £274. The house has been voted the ‘people’s favourite home’ by the Expo’s 30,000 visitors.

Situated in Milton of Leys, Inverness, the three-bedroom property has a Scottish larch cladding external finish to the exterior walls. The cladding forms part of NBT’s Pavaclad system, which features Pavatherm Plus woodfibre boards installed in a continuous layer over the timber frame, with infill insulation between the studs and OSB boards used on the internal face to provide racking strength and airtightness.

A similar approach was employed for the insulation of the zinc-covered roof, with NBT’s Pavatherm Plus woodfibre boards fixed over the rafters, and infill insulation between them. Both systems achieved impressive U-values: 0.26 W/m2k for the walls and 0.15 W/m2k for the roof, the targets set for this development. Configurations of these same NBT systems can deliver performance up to the highest PassivHaus standards if required.

With a high performing building envelope identified as the number one priority for the new build house, high performing insulation systems were a must, and having been impressed by the performance of NBT’s systems in previous constructions, Malcolm Fraser Architects were very keen to specify them for this latest project.

Neil Munro, project architect and senior architect at Malcolm Fraser Architects, comments: “We set out to design a sustainable and energy efficient alternative to a standard kit house which could be easily mass produced. We decided to avoid environmental “solutions” that require on-going maintenance and therefore accrue additional costs during the lifespan of the building. Instead, we focused on the simple, reliable and zero maintenance solution provided by NBT’s woodfibre insulation systems: a highly insulated external envelope.”

Being manufactured from over 95% recycled timber, and drawn from FSC approved sources, NBT’s woodfibre insulation fulfills the sustainability criteria for the home, whilst simultaneously delivering ultra high levels of thermal performance. In addition, when installed within NBT’s high performing insulation systems, the woodfibre insulation creates a fully breathable construction, thereby maintaining a healthy environment, with reduced risk of mould formation and the associated health risks to occupants.