The most vapour permeable complete airtight membrane in its class

Searching for an airtight solution when it comes to controlling ventilation and meeting global warming targets?

Roof underlays commonly act as a major line of defence with regards to air leakage from domestic properties, and the latest product on the market from Glidevale has really got people talking.

Here’s the science bit: Airtight underlays contribute to the management of wind load pressures and, by their very nature, minimise uncontrolled air leakage in to or out of a roof space. Vapour resistance figures achieved by air permeable roof underlays allow for the moisture vapour transfer via uncontrolled air leakage through the membrane. The vapour resistance of the new Protect VP400 PLUSLR is achieved via diffusion only making it the most vapour permeable, completely airtight membrane in its class.

By contrast permeable (air-open) membranes can allow the passage of air at the rate of up to 36m3/hr/m2 @ 50Pa pressure. This is more than 3.5 times the air permeability currently permitted under Building Regulations and will have a detrimental effect on the energy performance of any dwelling constructed without a flexible air barrier membrane at ceiling level.

So, if it’s an airtight solution to complying with current building regulations, as well as doing your bit to save the planet, then the choice in breathable membrane is clear.