High-Performance Timber Frame Build - Croydon

Passive Purple Airtightness System in Action

This Croydon-based timber frame project set out to achieve more than just compliance; it aimed to deliver a high-performance, future-ready home with exceptional airtightness, energy efficiency, and long-term durability.

Through a carefully planned approach and the application of Intelligent Membranes’ Passive Purple system, the project demonstrates what can be achieved when modern materials meet precision detailing. 

The Challenge: Achieving True Airtightness

Timber frame construction presents unique challenges when it comes to airtightness:

• Multiple junctions and connection points
• Risk of air leakage through gaps, seams, and service penetrations
• Requirement for a continuous, uninterrupted airtight layer
• Need for additional protection against moisture ingress and radon gases

Traditional methods often rely on tapes and membranes that struggle to maintain consistency across complex details, increasing the risk of performance gaps.

The Approach: A Fully Integrated Airtight Envelope

External Protection

Passive Purple External Brush was applied to all:

• Joints
• Junctions
• Structural connections

Before the application of Passive Purple External

This ensured a weathertight and airtight external barrier, sealing potential weak points before they could become issues.

Internal Airtightness Layer

A continuous application of Passive Purple Internal Airtight Vapour Control Membrane created a seamless internal envelope.

Unlike traditional sheet membranes:

• It flexes with the building structure
• Bonds directly to substrates
• Seals even the most awkward junctions with ease

Application Process: Precision Meets Simplicity

The installation process was designed to maximise efficiency while maintaining performance:

• Substrates prepared and cleaned for optimal adhesion
• External joints and junctions sealed using Passive Purple External Brush
• Internal airtight layer spray-applied across the full envelope
• Critical details reinforced to eliminate weak points
• Coordination with follow-on trades ensured integrity remained intact

The result was a fast, controlled installation process with minimal complexity compared to traditional systems.

Airtightness, Done Right

Airtightness is one of the most critical elements in delivering a high-performance building.

By utilising a liquid-applied system, this project achieved:

• Complete continuity of the airtight layer
• Elimination of gaps, overlaps, and weak joins
• Reliable performance across all junctions and penetrations

The Results: Exceeding Expectations

Airtightness Result: 0.17 ACH

This exceptional result:

• Far exceeds standard building regulations
• Enters Passivhaus-level performance territory
• Demonstrates the effectiveness of a fully sealed building envelope

Performance Benefits

• Significantly reduced heat loss
• Lower energy demand and running costs
• Improved internal comfort year-round
• Enhanced durability of the building fabric
• Protection against air leakage, moisture, and radon

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