TETHERA

The brief was to design an ultra-sustainable, comfortable and calm home, in fitting with its spectacular surroundings of Ullswater and certified to Passivhaus standards.

Tethera replaces an existing 1950s bungalow which had reached end of life. The bungalow was demolished and replaced with a Passivhaus certified new home. The house is a simple rectangular form with a cathedral-like roof extending its full 14m length, designed to maximise views of the lake. The open plan living area, dining space and kitchen occupies the double-height half of the home; the other half contains the bedrooms and bathrooms, with a mezzanine floor above. The finished house is superbly comfortable and ultra-low energy and has been made possible by measures which include highly insulated and airtight external walls and roof, triple glazed windows and a MVHR ventilation system.

The house is purely electric, and the small amount of heating required is from two towel rails in the bathrooms. Most of the electricity is provided by the solar panels on the roof and the battery storage, meaning that Tethera consumes very little energy with modest running costs.

The planning considerations were critical because of its location in the Lake District National Park and UNESCO World Heritage site. The planners required that the new house kept the same form and ridge height as the original bungalow and to use the same palette of materials as the neighbouring houses (white render and local slate roof). The design responded to these constraints, by creating a modern interpretation on the local vernacular; extra space was gained by lowering the floor level giving an extra mezzanine level and helping to ground the building on the site. The planners and local community were very supportive of the sustainable design and the project gained planning permission in six weeks with no conditions.

The house is made from prefabricated insulated timber panels, manufactured locally in Appleby. The frame was skilfully erected by the frame manufacturer in less than two days straight after lockdown. The rapid erection of the frame meant that the building was watertight within a few days – ideal for the wet and windy Lake District climate. Concrete was minimised and only used in the ground floor slab using 50%. GGBS cement replacing concrete. The use of wood was maximised and sustainable insulation – recycled newspaper and sheep’s wool – was used in the walls and roof. All the paint is VOC free Graphene helping to keep the indoor air quality as good as possible. The existing roof slate tiles were salvaged, and local slaters skilfully repurposed the slate for the new roof.

The smooth planning process and the use of a prefabricated frame meant that the house was completed in around six months, with most of the work taking place as we emerged from lockdown. A superb team of local trades worked on the house, and they all fully embraced the necessary skill, care and attention to detail required to build a Passivhaus. The budget was fixed and finite, and so the design and specification had to work hard – although the sustainable elements of the design were the main priority, and no compromises were made to achieve Passivhaus certification.