housing
Hayhurst and Co., 2021
25 Jansons Road, N15 4JU
RIBA House of the Year: A new exposed CLT-frame house, built on a site once occupied by market garden greenhouses, featuring a planted façade with sliding external screens and a riad-style central atrium, assisting in natural daylighting, ventilation and cooling.
Seven Sisters
Seven Sisters, South Tottenham
149, 243
The area around the site and small woodland opposite was once used as market gardens, with several greenhouses and allotments having been present historically.
The concept for Green House draws on this history and the verdant nature of the site’s surroundings, providing a contemporary re-imagining of a domestic greenhouse, blurring the boundaries between inside and outside spaces.
The house is constructed using a Cross-Laminated Timber (CLT) structure, which is exposed internally and treated with a fire-resistant coating. The end grain of the wood has been deliberately exposed throughout the house and visually shows the cross-lamination of the timber staves.
The spruce timber is grown in Austria and the CLT manufactured and panels and beams cut to size in an Austrian factory, then brought to site on lorries. The CLT frame was assembled on site using a crane in 2 weeks.
• The structural frame has a total of 52.9m3 of CLT.
• It takes 3 minutes to re-grow this amount of wood in the Austrian forest on a summer day.
• 39 tonnes of carbon dioxide was removed from the atmosphere whilst the spruce trees were growing. 3 tonnes were emitted during manufacture of the CLT and 1 tonne in transportation, meaning the net carbon footprint of the CLT structure is -35 tonnes.
The south-facing façade is planted with bamboo with sliding polycarbonate screens over. The bamboo and polycarbonate screens provide solar shading on hot summer days and provide softly filtered daylight and a feeling of openness whilst maintaining privacy throughout the year.
The central riad-style atrium connects the upstairs and downstairs living spaces and brings daylight into the heart of the house, where side-facing windows would not have been possible due to neighbouring properties. The atrium also assists in cooling the house in hot days through natural stack ventilation. The opening windows are fitted with temperature and rain sensors- they open when the internal temperature gets too hot and close when cooled down or raining.
Curtains wrap around the perimeter of the central space to allow the ground floor living spaces to be separated off and to assist with acoustic absorption in the space.
The house is heated using an air-source heat pump, which is able to draw heat from the outside air at temperatures as low as -20°C. Solar panels mounted on the roof assist in powering the electricity needs of the house and also feed into the heating system, heating the hot water tank whilst electricity demand in the house is low, acting as a battery storing energy harvested during the sunniest times of the day in the form of hot water for later use.
Working with a tight budget, many of the materials used in the house have been creatively re-purposed from their originally intended uses, including:
• The upstairs floor finish is cork rubber, originally designed for industrial gaskets.
• The black external cladding material is recyclable cellulose-bitumen agricultural roofing sheets.
• The planted façade screens are clad in polycarbonate roofing sheets.
• The curtains are made from trouser fabric by a friend of the owners.
• The external paving was made by the owners from concrete breeze blocks with a jesmonite surface, ground down to a smooth finish.
• The shower tray, downstairs sink, bath panel and kitchen worktops were all made by the owners using jesmonite mixed with recycled materials and gravel.