Walters Way

A substantial retrofit on a 1980s Walter Segal detached self-build house to create a highly energy efficient property that is both comfortable to live in and aesthetically pleasing.

About this project

One of 13 self-build houses on Walters Way designed by famous architect Walter Segal, the property was completely refurbished and insulated with natural materials including wood fibre board to bring it to near Passivhaus standards.

As part of the sustainable retrofit, the homeowners added a small extension to the property, rebuilt and insulated the roof, insulated the entire house, added triple glazing to windows and doors and installed solar panels.

Use of timber

The original property was built using timber frame. During the retrofit, the owners replaced the windows with triple glazing, FSC timber frames and aluminium cladding. The walls were insulated using wood fibre boards and lime render, resulting in a U value of 0.18 and 0.17 in the new extension.

As the property is built on stilts, the floor was insulated underneath using a combination of sarking boards and wood fibre boards together with the existing glass wool, delivering a U value of 0.15.

The roof was insulated using a combination of glass wool, hemp and cotton bats, cellulose fibre insulation, wood fibre boards and wood waste, delivering a U value of 0.14.

Retrofitting for energy saving and efficiency

The owners aimed to refurbish the house to deliver a highly energy-efficient and environmentally friendly property, drawing from a wide range of techniques and materials.

This thoughtful process meant recycling materials where possible, using natural materials such as cellulose and wood fibre insulation, installing solar PV panels, solar water heating, passive ventilation and mechanical ventilation heat recovery, water saving devices and low energy appliances and lighting.

The property also includes a two storey Passiv solar chimney which cleverly provides passive heating in winter and active cooling in summer.

Once completed, the house was assessed by SuperHomes, a network of more than 200 energy aware households that are eco-friendly, sustainable, low energy and low carbon. As a result it was awarded a carbon saving of 73%.

In harmony with the original design 

It was important to the owners to maintain the look and aesthetic of the original design to ensure that the house still fitted in with its neighbours. One element of the original property is a large roof overhang which blocks the high sun in the summer. It was important to keep that element when the roof was re-built, as this feature plays an important role in keeping the property cool in summer.

More information


Watch the video about the retrofit here

Photography: SuperHomes


Key contacts


Paul Capel & Alice Grahame

Insulation system suppliers



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