Pipers Square in Charlestown, Dublin is one of four projects currently under construction by Cairn, Ireland’s largest housebuilder. Alongside the other three sites, Pipers Square represents the company’s first foray into delivering residential accommodation to the Passivhaus standard, with more than 1,700 units being delivered.
The Proctor Group’s external air barrier, Wraptite, is part of the external wall specification at Pipers Square. In addition, the Group’s technical services team assisted Cairn with U-value calculations, and a condensation risk analysis to explore the effect of vapour permeable insulation.
The decision to construct Pipers Square to the Passivhaus standard is even more remarkable than simply the number of units being delivered. The site was acquired with planning permission for a scheme that was never designed with the Passivhaus standard in mind. A feasibility study carried out by Cairn allowed them to make the commitment to Passivhaus.
The apartment building specifications required only minor tweaks to the building fabric performance of the floors and roofs. An upgrade to triple-glazed windows was also required.
“The building regulations in Ireland are already quite onerous,” said Tony Ruth, Regional Sales Manager for the Proctor Group in Ireland. “The gap between the regulations and Passivhaus is not as significant as it might be elsewhere. Our Wraptite membrane was already part of the Pipers Square specification, playing an important role in delivering weathertightness and as-built performance.”
Wraptite is a Passivhaus-certified component, reinforcing its credentials as a high-quality product suitable for use in Passivhaus buildings. That it was already part of the external wall specification serves to demonstrate the existing ‘quality assurance focus’ of Cairn Homes. It also helps to show why the move to Passivhaus certification was less complicated than could otherwise have been the case.
Wraptite is an airtight and vapour permeable membrane with a W1 water penetration classification. It played a crucial role at Pipers Square in conjunction with an internal airtightness line. “The external weathertight layer mitigates airflow within the building fabric and avoids ‘thermal looping’, allowing the insulation to perform at its best,” said Jamie Lacey, Technical Manager at Cairn. “In addition, early application of the Wraptite membrane allowed Cairn to commence internal works sooner, and with confidence.”
The vapour permeability of Wraptite also allows the passage of moisture vapour and helps to eliminate any condensation risk in the wall. With the decision to adopt the Passivhaus standard, Cairn worked with the Proctor Group’s technical services team to fully assess the external wall build-up for any moisture risks. A comprehensive condensation risk analysis, carried out using WUFI software, showed the proposed build-up was not subject to any moisture risk due to condensation. proctorgroup.com/products/wraptite