Overview

The client wanted to see exactly what Passive Purple could achieve in a real-world airtightness application. On this project, we delivered full surface coverage — including floors, walls, and ceilings — ensuring that each flat was individually airtight.

The process began with Passive Purple Brush, sealing all connection joints, large gaps, and floor-to-wall junctions. Once these critical areas were reinforced, we applied Passive Purple Internal Vapour Control across all surfaces. The result was a continuous, seamless airtight layer that also acted as a robust radon barrier, protecting occupants from both air leakage and harmful ground gases.

BACKGROUND

The install only took one day, as we ran into zero problems. We love a challenge but we also love a hassle free project. We even astounded the air tester! A complete airtight apartment with an intelligent liquid management system.

SOLUTIONS

With a Passivhaus certified score of 0.03ach (20x lower than the required 0.6ach) Passive Purple can guarantee you a score of 0.6ach (air changes per hour) and under. Whether you’re trying to achieve certified. Passivhaus or just build to a Passivhaus standard, Passive Purple is your answer

RESULTS

The air test results were extraordinary: the air tester found the score so exceptionally low that he thought his machine was malfunctioning. After recalibrating, it was confirmed that the score was indeed accurate, achieving a value ten times better
than the standards for a passive house. These flats now boast an air test score of 0.035 ach (air changes per hour).

What Is Air Testing?

Air testing — also known as an airtightness test or blower door test — measures how much air leaks in or out of a building’s fabric. Using a calibrated fan fitted to an external door, the building is pressurised and depressurised while sensors record the airflow required to maintain a set pressure.

The result is expressed as Air Changes per Hour (ACH) at 50 Pascals or in m³/(h·m²) @ 50 Pa, showing how well the building envelope resists unwanted drafts.

Air testing is essential for:

• Energy efficiency – Reducing heating and cooling losses.

• Comfort – Eliminating cold drafts.

• Compliance – Meeting Building Regulations and Passivhaus/EnerPHit standards.

• Quality assurance – Ensuring construction work meets design airtightness targets

CLIENT FEEDBACK

"This is the first time I’ve worked with a liquid membrane, but Passive Purple delivers the results this industry is crying out for!"