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Low impact house, North Wales

A timber selfbuild project in North Wales has been designed to be low impact and energy efficient and was built with timber from local British woodlands. The house design was based on building principles of Architect Walter Segal, who designed building in the 1970s so that anyone could build a house using standard size off-the-shelf timbers and boards. The building was designed by Andy Hales and project-managed by the client Rob Rogers, an experienced builder and joiner, who brought in and managed local trades to construct the project over 2 years and to a budget of £150K.

21° supplied PERFORMANCE triple glazed timber windows and doors for the project.


The 2 bedroom house was built on the site of an old wooden mine manager’s hut. The Walter Segal-inspired design is similar to many of the buildings at the nearby Centre of Alternative Energy Centre in Machynlleth.  As the plot was in North Wales and at the bottom of a hill, Rob decided that the wooden stilts, usually found on Walter Segal houses, were too risky and so the house was built instead on brick stilts.

Rockwool insulation was used in the walls, floor and ceiling and careful attention was placed on airtightness detailing. The house’s air test came in under 3 ach/hour. The house is heated with a wood burning stove, with the rest of the house using electric heating helped by a 3.99KW solar panel array.

Use of timber throughout

The whole house was built with timber from local British woodlands. Douglas fir was used for the frame of the house and Larch used for the cladding. The wood was sourced from within 100 miles of the house and Rob often had to coordinate collection of the timber directly from the woodlands. The fence posts and balcony are made from sweet chestnut, the internal doors are made from reclaimed scaffold planks, and all the shelving in the house is made from green oak. The roof was the exception and was made of galvanised corrugated sheeting, which was factory-coated In Plastisol.

Triple glazed timber windows & doors

Green Building Store’s triple glazed timber PERFORMANCE range, with outward opening windows, an entrance door and French door were specified for the project. Finishes were ‘Nature effect’ clear woodstain inside with a timber finish in RAL 7023 on the exterior. Aluminium cills (180mm ) in a matching colour were used and, as the house is a bungalow,  all the windows and doors were to the Secured by Design standard.

The windows and doors are fantastic. They look really good and everyone comments on them. I chose Green Building Store windows and doors because I wanted timber to fit in with the rest of the house and I liked the fact they were triple glazed. Local joiners offering triple glazing did not offer the same specification or design and were effectively just extending the rebate of double glazed windows. The airtight seals and 10 year guarantee offered by Green Building Store were also important factors.

Rob Rogers

Project details

Building design

Andy Hales



Case study


Life changing homes