Timber Frame Passive Extension

We extended this house for Gerard Menezes in Glasnevin, Dublin in 2008 from 80m2 to 150m2 and did some renovation work to the existing house. The 70m2 Timber Frame Passive standard Extension arrived to site from our factory fully finished and insulated with the plasterboard on the walls and the windows fitted. It has excellent U-values of 0.11 for the roof, walls and floor so we expected a really good performance from this extension but the performance far exceeded our expectations.

All the Cold bridges were eliminated using our “Passive Slab” foundation system, we got an EnerPhit Air-tightness result of 0.95ACH@50kPa for the complete house which shows that taping the joints in the OSB board works really well. The main air losses from the Timber Frame Passive Extension were through the Rationel windows which leaked at the seals. We pumped 400mm of Cellulose into the roof of the existing house and did air-tightness work around the windows and ceiling.

The existing house was Externally insulated with 120mm of plastered EPS and Heat Recovery Ventilation was fitted. We ran this house through the Passive House Planning Package Software and got an amazing result of 23kwh/m2.a which meets EnerPHit standards, making it Ireland’s first.

This house was featured in a Construct Ireland article and has a BER cert giving it a B2 (90kw/m2.a) showing the inaccuracies of the BER system "This extension follows our ethos which is to reduce the need for heat to a level which makes the heating system irrelevant".

This is the wall build-up we used for the Timber Frame Passive Extension.