View of open-plan Passivhaus living room

Fabric first: what does it mean for your project?

The structural efficiency of your home affects the amount of heat needed to warm it

By Becca Green | 3 November 2020

Ensuring the structure of your home is well insulated and has a high level of airtightness is known as taking a fabric-first approach.

Joe Stuart – the innovative self-builder behind the Grand Designs affordable Passivhaus and founder of Warehome – offers advice on how to go about it.

View from dining area through to the living area and kitchen in a well insulated home with double-glazed windows

This London was built to near Passivhaus standard airtightness. Photo: David Giles

Build material

The construction method and materials you choose have a significant impact on the thermally efficiency of your home. For instance, concrete structures take longer to heat up, but they also retain heat for longer than one constructed from a lightweight timber frame. This is because concrete has a high capacity to store heat, known as high thermal mass. It applies to any dense material such as brick or stone. Conversely, a lightweight timber-frame house will reach a desired temperature faster, but it will be harder to maintain.

The role of insulation

The type, thickness and position of insulation plays a huge role in how well the heat inside your home is retained, and how little is lost to the outside. The most important thing is that your insulation forms a complete and unbroken seal around the house. Pay close attention to insulating the joins between different materials and structures to avoid warmth escaping.