Overview – Airtight Timber Frame Construction with Passive Purple

On this high-performance timber frame project, our outstanding airtightness results are a testament to the advanced sealing methods and precision application techniques used throughout the build.

By utilising the full Passive Purple airtight membrane range, we created a robust, flexible, and long-lasting building envelope that delivers exceptional external and internal airtightness. These liquid-applied solutions not only prevent air leakage but also provide an added barrier against radon gas ingress, ensuring long-term health, comfort, and energy efficiency.

Background – Sealing Joints and Junctions with Passive Purple External Brush

The first stage of the airtightness process involved applying Passive Purple External Brush weatherproof membrane to every joint and junction in the timber frame. This critical step seals potential weak points where air leakage and water ingress are most likely to occur.

To achieve a continuous and high-performance barrier, the entire external surface—including all connection points—was coated. This created a seamless, watertight, and airtight envelope, maximising durability, energy efficiency, and weather resistance for the building.

Solution – Achieving Superior Airtightness with Passive Purple

On this timber frame project, the combined use of Passive Purple External Brush and Passive Purple Internal Vapour Control demonstrates how detailed sealing and precision preparation are essential for achieving exceptional airtightness and energy efficiency.

This meticulous application not only meets but exceeds industry airtightness standards, ensuring zero unwanted air leakage, optimised thermal performance, and enhanced occupant comfort. The additional radon barrier protection reinforces our commitment to building safe, healthy, and high-performance homes.

By creating a continuous airtight and weather-resistant envelope, this approach delivers long-term durability, superior moisture control, and energy savings for years to come.

Results – Outstanding Airtightness Performance with Passive Purple

This timber frame project achieved an exceptional airtightness score of 0.17 ACH, far surpassing standard building regulations and proving the unmatched performance of Passive Purple airtight membranes.

Such an ultra-low air change rate drastically reduces heating and cooling demands, translating into significant energy savings and enhanced thermal comfort for occupants. This result also ensures a healthier indoor environment by eliminating draughts, preventing condensation, and maintaining stable indoor temperatures year-round.

Air Testing – Ensuring Airtightness and Energy Efficiency

Air testing—also referred to as air permeability testing, air leakage testing, or air pressure testing—is a critical process in high-performance construction. It measures how much air escapes through a building’s envelope, identifying any leaks or weak points that could compromise energy efficiency, comfort, and building durability.

In airtight construction, such as Passive House or low-energy buildings, achieving a low air change rate is essential. Air testing uses specialist equipment, such as a blower door fan, to pressurise and depressurise the building, pinpointing exactly where air leakage is occurring.

By carrying out air testing at multiple stages during the build, we can verify that products like Passive Purple airtight membranes are delivering the expected performance. This allows us to seal problem areas early, reduce heating and cooling loads, and guarantee compliance with stringent airtightness standards.

The benefits of thorough air testing include:

• Lower energy bills through reduced heat loss.

• Improved indoor comfort by eliminating draughts.

• Better moisture control, preventing condensation and mould growth.

• Enhanced durability of the building envelope.