Passive timber frame system

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Passive principles

Our Passive timber frame system supports projects designed around Passive principles and those pursuing Passivhaus Certification. We prefabricate each structure in our Herefordshire workshops, precision-engineering every element to deliver exceptional thermal performance and airtightness.

Choose from wall depths of 240mm, 300mm, 360mm or 400mm, achieving U-values from 0.15 down to 0.10 W/m²K, giving you confidence when targeting demanding performance standards.

Our Passive roof system offers cut, vaulted and flat roof options, achieving U-values between 0.13 and 0.10 W/m²K. When we combine this with an ISOQUICK® insulated Passive raft foundation, we create a continuous, thermally efficient, airtight envelope that wraps the entire building and minimises thermal bridging.

Whether you’re designing a contemporary home or a more traditional form, we give you the freedom to realise your vision without compromising performance.

Passive timber frame system

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Architectural finishes

This aesthetic layer is customisable to work with any Architectural design style.*

*supplied by others

Ventilated cavity for moisture control

This is a crucial gap that protects the timber structure from direct contact from weather while allowing for essential drying and breathability.

Vapour-open breather membrane

This membrane protects the wall structure from the elements, while allowing
moisture vapour to escape, ensuring long-term hygrothermal stability.

Weathering and structural sheathing

This OSB3 sheathing provides immediate structural rigidity (racking) and a robust breathable protection layer.

Passive wood fibre thermal insulation core

STEICOzell® natural, low-carbon wood fibre insulation delivers an exceptional U-values, eliminating thermal bridging and ensuring superior year-round comfort.

Primary airtight barrier

This engineered SmartPly ProPassiv® airtight OSB panel is the single most critical layer for achieving Passive House levels of airtightness.

Service-void & airtightness protection zone

This dedicated internal space is used for running electrical and plumbing services through, whilst ensuring the critical airtight layer remains completely uncompromised.

Internal finish & fire resistance layer

This layer provides a smooth, ready-to-decorate internal surface while contributing to a certified 30-minute fire resistance rating for enhanced safety.*

*supplied by others

Reinforced concrete floor slab

This robust, reinforced base provides structural integrity above the insulated foundation system.*

*supplied by others

Integrated ground protection membrane

This continuous barrier shields the entire structure from ground moisture
and, where necessary, from harmful radon gas.*

*supplied by others

ISOQUICK® insulated shuttering foundation system

This is the core of the Passive Raft foundation. This continuous, structural insulation has excellent thermal efficiency and minimises heat loss at the crucial floor-to-wall junction.*

*supplied by others

Foundation blinding layer

This is a compact layer for achieving a level and stable working surface, essential for the precise installation of the ISOQUICK® system.*

*supplied by others

Open graded drainage & load-bearing sub-base

This deep, graded base provides ultimate load support and ensures effective drainage beneath the entire foundation.*

*supplied by others

Ground filtration & separation geotextile layer

This separation layer between the granular sub-base and native soil prevents contamination and maintains the sub-base’s optimal drainage properties.

Key features

Ultra-low energy demand: Reduces heating and cooling costs by up to 75% compared to conventional new builds.

High airtightness: Guaranteed airtightness of ≤0.6 air changes per hour.

Healthy indoor environment: When paired with MVHR, provides fresh, filtered air and stable temperature and humidity.

Natural, low-carbon materials: Uses STEICOzell® wood fibre insulation and responsibly sourced timber.

Breathable construction: Hygrothermal design helps manage moisture and reduce condensation risk.

Sustainable build-up: 81% wood fibre composition; renewable with low embodied carbon.

Precision off-site manufacturing: Factory-built panels ensure accuracy, speed, and minimal waste.

Efficient on-site delivery: Pre-insulated panels reduce build time and overall costs.

Fire tested: Certified to BS EN 1365-1:2012 (loadbearing wall) and BS EN 1363-1:2020.

Moisture management: Improves air quality and long-term durability.

Passive House-level insulation: Full thermal envelope for maximum performance.

Structural performance: Engineered for strength in high-performance timber frame systems.

Faster build programmes: Pre-planned and installed efficiently by our in-house team.

Passive range of products

Passive wall system

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Passive roof system

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Passive foundations

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