Wraptite-SA passes Passivhaus air tests with ease

Wraptite-SA the high performance airtight membrane from the A. Proctor Group has easily surpassed the initial air test targets for an exciting new children’s home project. The Anchorage at Dibden Purlieu is one of five buildings currently being built for Hampshire County Council to Passivhaus standard, which will help to achieve a significant reduction in energy bills for each property.

In order to successfully achieve the Passivhaus standard, buildings are subject to rigorous quality control, and are required to have air tests carried out during the construction process and upon completion. The development at the Anchorage was designed requiring an airtightness level of less than 0.5. Wraptite-SA was applied externally to the timber frame panels in continuous pieces by chartered building company Raymond Brown Building creating a highly insulated and sealed finished building, and achieving the required standard. Initial air test results of 0.43 were achieved coming well below the 0.5 air permeability target. All the more impressive, since this was recorded even before the installation of the internal VCL Procheck 500, also provided by the A. Proctor Group, whose recommendation is that advice is sought when detailing Passivhaus to assess whether a VCL is required. This will be dependent on the building system, insulation used and the standard of workmanship.

The use of Wraptite-SA, the only self-adhering vapour permeable air barrier certified by the BBA, makes a significant contribution to a building’s thermal performance by preventing lateral air movement. It also provides high vapour permeability, which allows any water vapour to escape the wall construction efficiently thereby reducing any interstitial condensation problems.

Traditional use of internal air barriers can also be more complex and costly to install, due to the need to accommodate building services such as electrical, lighting, heating and drainage systems.

The final houses will be quite traditional in appearance with brick walls, stone ills and tiled roof, but this exterior will conceal a hi-tech construction using SIPs (Structural Insulated Panels), fully tanked and insulated ground floor slab with pre-run services, solar panels and superb en-suite facilities providing homely but durable accommodation for Hampshire Children’s Services.