The Wraptite external air barrier system from the A. Proctor Group is achieving efficient airtightness at two new-build extensions to the Connolly Hospital in Dublin. The project consisted of two phases, with a new laboratory building in phase one, and a brand-new A&E facility constructed in phase two.
The Wraptite system is the only self-adhering vapour permeable air barrier certified by the BBA and combines the critical properties of vapour permeability and airtightness in one self-adhering membrane. This approach saves on both the labour and material costs associated with achieving the energy efficiency demands in buildings.
Air leakage through cracks, gaps, holes and improperly sealed elements such as doors and windows can cause a significant reduction in the performance of even thermally insulated envelopes, in some cases, reducing their effectiveness by up to 70%. In addition, unmanaged or uncontrolled airflow can act as a carrier for moist air, drawing it in from the outside or pushing it from the inside outwards, into walls, ceilings and roofs. The impact of this uncontrolled moist air movement can have a detrimental effect on the life of the building and the health of its occupants.
The high vapour permeability of the Wraptite air barrier allows the substrate beneath to dry quickly and moisture vapour to escape, reducing the likelihood of mould, mildew, condensation, timber distortion and metal corrosion.
Designed by architects MCA Dublin, award-winning drylining contractors McLaughlin Taylor of Donegal installed the Wraptite System as an external air barrier and alternative to a traditional standard breather membrane. The use of conventional membranes would have required mechanical fixing and added to the installation time. As an alternative, the Wraptite self-adhesive membrane was applied externally, quickly and easily to the external steel frame in continuous pieces.
Gio Fusco of McLaughlin Taylor commented: “The application of the self-adhesive Wraptite System was quick and easy to apply in a single application, with no requirement to return for additional fixings. We used Wraptite for both phases, and the air permeability test results were consistently excellent with both buildings achieving a rating of close to or just below 2m3/hm2.”
Internal air barriers can be complex and costly to install due to accommodating building services such as electrical, lighting, heating and drainage systems. Positioning an air barrier on the outside of the structural frame simplifies the process of maintaining the envelope’s integrity, with fewer building services and structural penetrations to be sealed.
By reducing the likelihood of potential failures to meet designed airtightness levels, the Wraptite System helps ensure “as-designed” performance, narrowing the performance gap between as-designed and actual energy performance.
