Backwell eco HOmeS
The practice obtained approval for the construction of two eco-homes in North Somerset, and followed through with detailed design of the first. The owners recently completed this house as a self-build project.
Planning was achieved as a departure from local policy, exchanging Permitted Development into approval for a pair of new build homes.
The striking design takes full advantage of the setting within the Somerset countryside, blending sympathetically into the surrounding countryside and maximizing views out. It substantially reduces the amount of hardstanding on site, and landscaping with native plants and trees increases the habitats for native flora and fauna.
Clad entirely in timber, glass and solar panels, the houses provide open plan, flexible, double-height living spaces that open onto private southern gardens via a planted patio that allows winter sun into the space whilst shading from the summer sun. The new buildings are highly insulated, benefit from passive solar-gain and are naturally ventilated through high-level roof lights. The roof lights and large glazing give good daylight throughout and all artificial lighting is LED. The homes require very little energy to run.
A holistic approach to sustainability was adopted, using passive design principles to reduce heat loss, and maximise the benefit from passive solar-gain. Passivhaus PHPP modelling was used to inform the design. The building fabric is highly insulated and airtight to Passivhaus standards.
The building was built using a pre-fabricated twin-wall timber frame, assembled on site in a week, and employs natural materials including cellulose-fibre insulation and self-finished larch cladding. The foundation and slab were designed as an insulated passive raft foundation, using 60% less concrete than a conventional strip foundation. Windows and doors are high performance triple glazed with low-e coating.
A variety of renewable energy technologies are included in the building. The large south-facing roof maximises the potential for solar energy generation, generating 7.2kW peak output, saving 4,188kg of carbon emissions per annum. A Mitsubishi Ecodan air-source heat pump with 200L thermal store provides space heating and hot water. Mechanical Ventilation with Heat Recovery (MVHR) was incorporated to maintain air quality and control indoor climate.
