Strawbales

This site was selected as the best location for the new straw bale buildings because of its close proximity to the farmyard and because of its great views over the Shropshire hills.

The only conventional aspect of the project is the base. It consists of concrete strip foundations around the edge of the buildings on which approximately 850 concrete blocks were laid to form the perimeter walls which carry the timber frame structure.

The straw build at Brynmawr Farm uses the timber frame construction method. This comprises of a timber floor insulated with 300mm of recycled bottle insulation on which is built a bespoke timber frame which sweeps around the curved walls of both buildings. The frame supports a flat roof system with a generous overhang to protect the walls from the worst of the weather.

The sedum roof was built up in many layers; geotextile, butyl liner, water retentive soil substrate Two large sky lights provide additional natural light to the large classroom beneath.

Aproximately 250 bales of wheat straw have been used to form the walls of the two buildings. Wach straw bale is trimmed and shaped to fitin between the specifically designed timber frame. The straw bales are laid flat in the structure giving the walls an average width of 500mm. Once all the bales have been installed and compressed for maximum thermal value, they are trimmed to give a flat, rigid surface ready for rendering.

The render is built up in 3 coats inside and out. The first coat is a mixture of lime and sand worked directly into the straw to provide a firm key for the following coats. The second coat contains chopped hemp and is trowelled onto the wall in a layer about 12mm thick. The top coat of render is a mixture of lime, a finner grade of sand and hemp fibres.

Lime wash is applied to the outside to give the render added protection and colour. The interior walls are finished with natural, breathable clay based paint. Wooden windows and doors have been specified with 24mm argon filled double glazed units to achieve good thermal preformance.

Finally, the decking and acess ramps were completed. The covered walkways provide weathger protection and link together the main building and toilet block.