Proctor membrane used on landmark Dublin passive scheme

This article was originally published in issue 52 of Passive House Plus magazine. Want immediate access to all back issues and exclusive extra content? Click here to subscribe for as little as €15, or click here to receive the next issue free of charge

Wraptite is both airtight and vapour permeable. Positioned on the outside of the external wall, it moves the air barrier away from the internal services zone, reducing the number of penetrations that need sealing while still allowing moisture vapour to escape. Proctor Group’s technical team carried out condensation risk analysis using the WUFI software to verify the wall build-up and confirmed no interstitial condensation risk, the company says.

Cairn, Ireland’s largest housebuilder, is now building passive house certified homes across multiple Dublin sites. The projects mark the company’s first foray into passive house construction, but the transition from Ireland’s nearly zero energy building (NZEB) standard proved surprisingly straightforward, the company says.

“The building regulations in Ireland are already quite onerous,” said Tony Ruth, regional sales manager for Proctor Group in Ireland. “The gap between the regulations and passive house is not as significant as it might be elsewhere.”

A feasibility study found that Cairn’s existing quality assurance approach made passive house certification readily attainable, as reported in issue 48 of Passive House Plus. The apartment specifications required no additional insulation, and Cairn was already using mechanical ventilation with heat recovery on some projects. The principal change was a switch to triple-glazed windows, along with a simplified heating system spec. Due to Ireland’s NZEB regulations, the average airtightness levels for new homes has been under 3 m3/hr/m2 at 50 Pa for several years, narrowing the gap to passive house.

The UK Passivhaus Trust has set a target of 10 per cent of new housing achieving the standard within ten years, up from around 1 per cent today. Ruth says the UK’s less stringent airtightness requirements and reliance on mechanical extract ventilation make an equivalent shift harder than in Ireland. Scotland is consulting on a passive house equivalent for its building regulations, he says, but England’s Future Homes Standard relies more on grid decarbonisation than fabric improvements.