What is the fabric first approach?

In a world captivated by fighting climate change and living an eco-friendly life, the simplest thing you can do is reduce the amount of energy you need to use in the first place.


The fabric first approach allows for simple changes considering the design, construction and building fabric of a home to produce an efficient and low energy building. So, to give you the best idea, let’s start with the ‘building fabric’.

So what is the building fabric?

The building fabric refers to the roof, walls, windows, floors and doors of a building. And within these elements, you can make smart choices as to which materials you use, to make sure your building needs as little energy as possible to keep it warm and comfortable all year round. Whether that’s choosing the right level and performance of insulation in your walls, floor and roof, how you reduce draughts, or the performance of the windows you choose.

Timber roof

What are the benefits of applying a fabric first approach?

  • Reduced energy costs
  • Improved temperature control
  • Comfortable all year round
  • Lower running costs
  • Reduced chance of condensation or mould (don’t forget to manage ventilation well)

It seems like a no-brainer to educate ourselves on the best materials for a building when there are so many benefits available.

Did you know?

Almost two-thirds of the heat generated in a home is lost through the building fabric. And up to 35% can be lost through uninsulated walls.

The amount of heat loss is not only dependant on the quality of the fabric, but also the internal and external temperature difference, and the amount of ventilated air entering the building.

Bricks being laid

So how can you apply the fabric first approach to your self-build?

Solar gain:

  • Think about your build orientation
  • Make good use of natural daylight
  • Redirect the sun using blinds
  • Consider the positions and size of windows on different sides of the building
  • Understand the passage of the sun across your building plot


  • Preferred lightweight options for their thermal and acoustic properties include glass wool and PIR (polyisocyanurate)
  • More rigid options include expanded polystyrene, phenolic foam, or even cork - all provide excellent thermal performance


  • Double or triple-glazed windows prevent air infiltration
  • Sealing gaps/cracks provides maximum efficiency
  • Trickle ventilators are great for background ventilation (you won’t even notice them they’re so quiet)

Heating and ventilation are part of the same process, so you must view these as friends for them to be effective and in balance.

Choosing your own materials is a crucial part of your self-build journey - learn more here.

Isover insulation

Other ways to reduce energy and use energy more efficiently can involve behavioural actions, such as opening/closing windows for ventilation, using blinds, closing doors etc. But for you to be able to boast about your eco-friendly home, always think about the fabric first. Once you’ve applied the best fabrics to your home, you’ll be laughing for the rest of the journey.

Design Materials