Airtightness – bridging the gap

The upgrade conversion of a 1964 brick and timber dwelling built by Mowlem (Scotland) Ltd involved an attic conversion, ground floor front and side extension, as well as a full height extension to the rear. On the front and side extensions, Goodburn Baillie (Architecture & Building) Ltd put Wraptite-SA from the A. Proctor Group Ltd to the test.

Refurbishments can be complicated projects, with timelines and project plans easily diverted by working with old and new, so it made sense to plan in safeguards against delays and the inevitable British weather.

It may surprise most to discover that the biggest material cost by quite a margin in a refurbishment like this is insulation. Given this expenditure, it is only prudent that the building be as airtight as possible, whilst still a breathing structure.Wraptite- SA combines important properties of vapour permeability and airtightness in one affordable self-adhering membrane.

Where a new structure joins an existing one, a potential weak point in terms of cold bridging and air leakage is created. Using a combination of compriband 600 and expanding foam behind a step detail, then covered with Wraptite tape (easier to work the narrower tape over the step) in preparation for the larger Wraptite-SA sheet, this weak junction is eliminated.

For further information related to the A. Proctor Group’s Wraptite-SA or any of their other product ranges, please visit