Canolfan Hyddgen - The First Certified Non-Domestic PassivHaus in the UK - a Q50 Air permeability of 0.37m3/hr/m2

JPW Construction of Machynlleth in Wales, have become pioneers in the UK construction market becoming the first company to receive PassivHaus certification for both a domestic and non-domestic build.

The non-domestic project Canolfan Hyddgen is a Welsh Assembly/Powys County Council funded scheme. The building is used for meeting rooms, night classes, drop in centre and as a council service point; with multiple occupancy it was critical that the building is versatile, comfortable and economic and with gas prices set to rise, this was one of the fundamental reasons to adopt a PassivHaus method of build, which would also address Powys County Councils carbon management programme of a target for a CO2 reduction of 30% by 2012 and 50% by 2017. The brief as well as achieving PassivHaus was also to achieve BREEAM excellent. Canolfan Hyddren actually went on to achieve 84.4% Excellent (the highest to date in Wales) and won the Welsh BREEAM 2009 awards for offices.

The building has a central masonary core with an external solid timber frame and I beam cassette roof. They incorporated the pro clima airtight building system, using Intello Plus Intelligent airtight vapour check along with pro clima’s Tescon No 1 tape and Orcon F glue and achieved a permeability result: n50 = 0.249-1 @ 50Pa (PassivHaus Institute requirement is 0.6) or a Q50 = 0.37m3/(h.m2) 50 Pa (UK measurement). This is a fantastic result and pays tribute to the attention to detail by on site personnel.

John Williamson of JPW reported that the greatest challenge was the unique thermal bridge free junction details, which the timber frame supplier could guarantee and the PassivHaus Institute would accept. The importance and responsibility of achieving these junctions, whilst ensuring airtightness continuity, was passed to the site team and then again to the M&E contractors to ensure a holistic result.

A decentralised ventilation system wtih timer and PIR controls was favoured due to the multiple and varied occupancy.

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