At an architect’s new timber frame home in Cork, Ireland, high racking strength and airtightness were crucial in the internal lining specification. With the installation of 240 sheets of the new SMARTPLY VapAirTight OSB3 panel, the house achieved an air change rate (n50) of 0.09 air changes per hour at 50Pa – six times better than recommended by the PassivHaus Institute.
Designed and built to passive standards by specialist manufacturer Shoalwater Timberframe Ltd., the stylish two-storey house incorporates a range of ecological materials and systems. But with its large glazed areas and two cantilevers at the rear and side of the building, the project required a structural panel that combined racking strength with exceptional airtightness – for which SMARTPLY VapAirTight proved ideal. “Developed from our OSB3 system, SMARTPLY VapAirTight has integrated vapour control and unrivalled air barrier properties and will help to close the gap between design and as-built performance,” said David Murray, Innovation Manager at SMARTPLY. “We monitored the system’s performance at every stage of the process and upon completion it far exceeded PassivHaus standards for airtightness.”
SMARTPLY VapAirTight is easy to handle and can be readily cut and fixed using standard timber frame fixings. Being robust, there is minimal risk of damage during assembly, transport or erection, which means the airtightness is not compromised. It is suitable for renovation as well as new build projects and applications include modular manufacturing as well as the production of SIPs and prefabricated roofing systems. “We insist on the highest quality materials in every timber frame we design and build,” said Donal Mullins of Shoalwater Timberframe. “With work on-site starting in January 2015, the site and the panels themselves endured every type of weather imaginable – providing perfect testing conditions for the new VapAirTight panels.” Due to the confined site and its challenging location, the issue of double handling provided additional testing for the panels and one which it passed with flying colours. Donal Mullins added: “Everything that happened gave the boards the opportunity to fail and they didn’t. And with SMARTPLY VapAirTight installed for approximately 98% of the internal linings, the system has certainly proven to deliver outstanding airtightness under real and challenging site conditions.”
The Shoalwater timber frame structure also made use of Coillte’s Medite Vent breathable MDF panel product as part of the roof construction. With SMARTPLY VapAirTight installed on the interior, over 230m2 of Medite Vent was used on the roof’s exterior to ensure external vapour diffusion and reinforce the roof’s racking strength prior to the installation of the cellulose blown-in insulation. Suitable for both new build and renovation projects, SMARTPLY VapAirTight is a versatile, strong and cost-effective OSB panel. The innovative new system is set to play a vital role in the delivery of high performance and airtight timber frame homes – when designed and built using a highly sustainable and fabric first approach.