Hen House by Paul Testa Architects is all about its environment – sustainability and its steep site
Sheffield is a famously hilly place – the ‘Côte de Jenkin Road’ was the steepest climb on the British stage of the 2014 Tour de France, incorporating a more-than-challenging 33% gradient. Over in the city’s south-western edge-suburb of Bradway there are similarly steep parts. One of those is owned by Gail Cooke and Jo Mallows. So when they commissioned Paul Testa Architects (PTA) to design them a house at the end of their one-acre garden, the garden in question was essentially a lush wooded ravine.
The couple had lived for eight years in an inter-war house at the top of the slope which looks across the top of the city to the moors beyond, an immense view. The plan was to downsize into a highly energy-efficient new home, divide the plot, and sell off their old home to cover the cost of the new-build with some to spare. They used to keep chickens on the site – hence the name Hen House, which stuck to become the official name of the new property. Before their ownership, the site had had a history of failed overlarge planning permissions, but this one sailed through.
PTA is a small but growing firm established in 2010 and now seven-strong, based at the top of another steep hill in the Sheffield University quarter. By the time I’d criss-crossed the city to visit both the house and the office with project architect Julie Maxwell, I was feeling the physical burn. But the house itself is a vessel of calm, docked in the side of its valley. It is very unlike the glass-and-steel boxes that sometimes seem to be the default architectural response to such sites. Cooke and Mallows were clear from the outset that they wanted to reduce their environmental footprint in various ways – not only in energy terms but also just the space they occupied. In consultation with Paul Testa, they decided on Passivhaus principles.
The design for Hen House rapidly evolved as a two-storey dwelling cut into the slope of the ravine below the existing house, not blocking its views. It is designed in two clearly-defined layers: an L-shaped plinth level in blue-grey engineering brick that continues as an enclosing lower boundary wall, and a lightweight rectangular-plan upper storey in laminated timber frame, the internal spaces rising to the underside of its cedar shingle roof. That’s an important feature since, with this topography, you look down from above onto that roof from the road outside. It takes the form of a relatively narrow west-oriented longhouse, with the asymmetrical roof itself responding to the slope, steeper one side than the other, and wrapping down and angled slightly inwards on the northern side to form the wall cladding there. Other exposed walls on the top floor are in Eternit fibre cement board while the plinth is enlivened by a frieze of Ibstock’s Sawtooth Umbra bricks.
The house is all about the experience of the top deck, the progress from the entrance porch formed by the projecting roof via an office-sized hall separated from the house beyond by a toilet and storage core. The long room is divided by a full-height plywood bookshelf which maintains views through to the large balcony overhanging the slope at the far end. From there you can see for miles.
So this is an exercise in light versus dark. The bedrooms are downstairs where the earth and masonry-sheltered construction, along with the shading slope above, help to keep a temperature equilibrium – noticeable in this year’s heatwave when the upper floor with its extensive west-facing end glazing got very warm. In fact, the lower level is essentially a different microclimate anyway, opening out onto a lower terrace excavated from the valley side, with outdoor steps leading down to it. A higher terrace at top floor level occupies the top of the plinth.
At £2,135/m2 including all external works, this is an economical house considering the Alpine terrain, the excavation and masonry plinth work required and the inclusion of kit such as a heat-reclaim unit. The structure took some value-engineering (‘We worked extremely hard with the clients, structural engineer and contractor to develop a proposal and construction method that was as cost effective as possible,’ says Testa) but the end result feels very good. This is a house that sits lightly in its landscape, with minimal running costs and maximum delight.