The Complete Internal Airtightness Kit
Making the inside of a building airtight means sealing the open walls and ceilings, the junctions, the penetrations and the prep — ideally from one coordinated kit so nothing gets missed on the day.
The problem with buying piecemeal
Buying internal airtightness products separately leads to mismatched quantities and missed details — and missed details cost you on the air test. With Approved Document L requiring every new dwelling to be pressure-tested, a coordinated approach to the whole envelope pays off.
The solution: the Big Boy Bundle
The Passive Purple Internal Bundle (Big Boy) brings together Passive Purple for the open areas with the brush grade, tape and sealant for the details — a complete internal airtightness kit, the right tool for each part.
What it covers
- Liquid membrane for walls, floors and ceilings
- Brush membrane for junctions and penetrations
- Tape for frames and board joints
- Sealant for gaps and services
Benefits
- Complete internal system in one bundle
- Covers open areas and details
- Passivhaus-certified components
Frequently asked questions
Is it enough for a whole house? Quantities depend on area — ask us to size it to your project.
Can I plaster over the finished layer? Yes — prime with Supergrip first.
Follow the method in How to Make a Building Airtight.