Fabric first: what does it mean for your project? - Grand Designs magazine
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 |

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.

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.

Aim for it to be airtight

With a fabric first approach, it’s important to be aware of gaps across the external envelope of the building – walls, roof, windows, etc. Even small holes can contribute to heat loss. So, regardless of the type of building material you choose, the level of air tightness contributes to how thermally efficient your house is.

A matter of glazing

Well-placed windows can capture the sun’s heat. While poorly sited ones can cause overheating. Upgrade to double or even triple glazing to reduce heat loss or gain. When planning your self build, take time to consider the implications of where you put the windows, and their size.

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