Our Vario® XtraSafe product line is a unique, airtightness and smart vapour control membrane that will help ensure the properties you are working on exceed the requirements for UK Building Regulations and, if necessary, can achieve better than PassivHaus standards of airtightness.
How is airtightness tested?
The test for airtightness is fairly straightforward. Sometimes called a blower door test, it sees a temporary, airtight screen fitted over the building entrance, which secures a fan in place (see picture below). Trickle vents and other ventilation routes are closed, and water traps filled. The fan is then used to draw air in or out of the property in order to create a pressure difference of 50 Pa between the interior and exterior of the building. The rate of airflow through the fan required to maintain the 50Pa pressure difference is recorded as the building’s air permeability (or airtightness level). This figure is used within the Building Regulations compliance calculation (e.g. SAP, SBEM etc.) to determine whether the building complies or not.
How can Vario XtraSafe help a property pass the airtightness test?
Vario® XtraSafe by Isover is an airtightness and smart vapour control membrane reinforced with Nylon. It’s three times the strength of polythene so it’s robust enough to be handled on building sites without suffering unwanted damage. Unlike basic airtightness membranes, Vario® XtraSafe is a smart vapour control layer, meaning that its pores open and close preventing unwanted moisture build-up in the building. This prevents moisture damage to the building structure and the potential for mould growth.
The membrane is simple to install and can be fitted by just one contractor, using our unique XtraFix tape and Vario® DS Sealant. The membrane comes in sheets with pre-printed cutting guides. These can also be used to cut holes for protrusions through the membrane such as pipes and cables. These holes can then be sealed with a combination of Vario® XtraSafe membrane, Vario® DS Sealant and XtraFix tape to ensure an airtight finish.
If applied to the entire building envelope, Vario® XtraSafe protects against interstitial condensation, the accumulation of moisture and other issues related to air permeation, making the building comfortable for those living and working in it, energy efficient and, of course, compliant with Building Regulations.
If you are working on a building project and want to make sure it will comply with airtightness regulations, you can complete our online form to make an enquiry about Vario® XtraSafe. One of the Isover team will be in touch as soon as possible to answer your query to help you decide if Vario® XtraSafe is the right option for your build.