Everything you need to make a building airtight, in one place. Our airtightness products work as one system: liquid airtight membranes for walls, floors and ceilings, airtightness tape for windows, doors and junctions, airtight sealants and grommets for gaps and service penetrations, and smoke testing kit for finding leaks before the air test does.
Liquid airtight membranes
Passive Purple and Airtight White are airtight membranes you spray, roller or brush straight onto blockwork, OSB, plasterboard and concrete. They cure into one continuous airtight and vapour control layer with no laps to tape and no staples to puncture it. Both are Passivhaus certified, BBA approved, tested to ASTM and EN standards (ICC-ES ESR-4715) and tested as radon and methane barriers. For façades and external walls, Passive Purple External is a fire rated (Class B) airtight and weatherproof membrane, and Passive Purple X brings Class B fire performance to the internal airtight layer. For existing buildings, the Retrofit Airtightness paints seal walls and ceilings without stripping back.
Airtightness tape
IM Fleece Airtightness Tape connects window and door frames, board joints and building junctions to the airtight layer. It has a plasterable fleece face and comes in 25m rolls in 75mm, 100mm, 150mm and 200mm widths. See our airtightness tape guide for choosing, sizing and installing it.
Airtight sealants and grommets
Passivhaus Airtight Sealant seals gaps, junctions and the edges of the membrane. The GOAT Liquid Grommet forms an airtight, flexible seal around pipes and cables straight from the tube, so you don't need a different grommet for every service size.
Find leaks before the air test
The Wohler S 100 Smoke Stick and smoke tanks show you exactly where air is getting through, so you can fix it before the tester arrives. Read how to pass an airtightness test.
Airtightness questions
What is an airtight membrane?
An airtight membrane is a continuous layer that stops air leaking through the building fabric. A liquid airtight membrane is painted or sprayed on, so it follows every corner, joint and penetration without laps. Read more in how to make a building airtight.
What airtightness do I need?
Building Regulations Part L sets a maximum air permeability for new homes, and Passivhaus targets 0.6 air changes per hour at 50 Pa. See Part L air permeability targets explained and how to hit 0.6 ACH.
Tape or liquid membrane?
Most projects use both: liquid membrane across the surfaces and tape at frames and board joints. See airtightness tape vs liquid airtight membrane.
Not sure what your project needs? Send us your drawings or call our technical team on 01223 208174.
