The fabric first approach to building design is Heralded by Build It as the “best route to achieving a comfortable, low-energy home for life”. But what is fabric first and what are its benefits?

It’s one of Streif UK’s go-to sustainable self-build concepts. Our precision-made offsite building systems provide the quality needed for Passive House Standards. What’s more, some of our award-winning projects have followed fabric first principles to achieve the ultimate in sustainable construction.

The fabric first approach defined

With a fabric first approach, the building does the work and energy efficiency is at the property’s core. From the design concept and throughout build, the performance of components and materials are optimised before mechanical or electrical services come into play. As Build It continues:

“A fabric first approach prioritises design and construction that minimises the need for heating and cooling.
This translates as passive solar design (harnessing the sun’s energy); lots of insulation; high-performance windows and doors; and good overall air-tightness, so that no drafts can get in and no warm air can escape”.

Fabric first construction quality

When it comes to retrofitting, a fabric first approach is about making repairs and draught-proofing before bolt-on energy devices like solar panels are considered. This reinforces the point that, no matter how sustainable the building design, energy efficiency depends on quality workmanship.

Streif’s advanced closed timber panel construction, manufactured offsite and to precision in our German factory, provides an airtight envelope. The quality control behind Streif’s sustainable building systems really comes into play for an optimum fabric first construction. We boast:

• Factory controlled conditions
• Rigorous quality auditing
• Tried and tested materials and methods
• Excellent airtightness
• Highly skilled workers

What is Passive House Standard?

Like Streif, Passivhaus was born in Germany and is the pinnacle of low-energy building design. Introduced by Adamson and Feist in 1991, the Passivhaus Standard is a construction concept.

It’s based on a set of principles that follow a fabric-first approach. And, as highlighted by Passivhaus Trust, reaching the Passivhaus Standard in the UK usually involves:

• Using the Passive House Planning Package (PHPP) for accurate design modelling
• High levels of insulation
• High performance windows with insulated frames
• Airtight building fabric
• Thermal bridge free construction
• A mechanical ventilation system with highly efficient heat recovery

Known as Passive House in the UK, buildings of a Passivhaus Standard are not only eco-friendly but also comfortable to live in and affordable to build and run. Key criteria for the Passivhaus Standard include:

Space heating demand – ≤ 15 kWh/m². yr
Space cooling demand – ≤ 15 kWh/m2. Yr
Airtightness – ≤ 0.6 air changes/ hr @ n50
Summer overheating – Max 10% > 25°C

Piggybacking on this, “passive design” works with the climate of the build’s location to balance comfortable levels of heating, ventilation and lighting. It considers the placing of natural resources – like sunlight, wind and vegetation –in the building’s design.

Fabric first principles

Here are some key fabric first principles, and Passive House standards, met by Streif’s sustainable building systems:

• Standard Streif wall panels can achieve a U-value of 0.17. This is better than requirements set by UK Building Regulations.
• Our high-performance building systems can achieve U-values as low as 0.12W/m2K. This meets Passive House and net zero carbon standards.
• We only use non-combustible mineral wool insulation products with an A1 fire rating in all our buildings.

Structural Timber Magazine Fabric First article

Streif UK fabric first building projects

Our build for Stoneham Park Primary Academy, Hampshire, used a low-energy fabric first approach.

Designed to Passive House standards, this two-storey educational building was based on fabric first principles and a Mechanical Ventilation with Heat Recovery (MVHR) system. These improved the school’s:

• Thermal comfort
• Indoor air quality
• Energy consumption

The sustainable Streif timber frame system was central to this new primary school. What’s more, offsite manufacturing allowed for the quality control synonymous with fabric first success.

We’re proud to say that this educational construction project was also a finalist in four categories, including Project of the Year, at the 2020 Structural Timber Awards.

To discuss your own fabric first approach building project or self-build vision, please get in touch with the Streif technical team who will talk you through your options.