Thursday24 July 2014

Prospect House, Sion Hill, Bath, by Dow Jones

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A striking zinc skin fitted over an eighties house in Bath demonstrates the architectural possibilities of refurb over new build

You might have thought upgrading the nation’s existing housing stock would be right at the top of both the government and the architectural profession’s agendas. Our homes produce 27% of the UK’s carbon emissions so this ought hardly be a case that needs restating. Indeed the previous government’s targets stated that as well as all new homes being zero carbon by 2016, the entire country’s housing stock should be zero carbon by 2050, implying the refurbishment of somewhere between 14 and 22 million homes. To a recession hit profession this ought to be manna from heaven and for a new government keen to promote itself as “the greenest ever” it ought to be a call to action.

And yet despite the new Green Deal, Pay as You Save and The Low Carbon Economy the recent budget gave little in the way of concrete support. The Sustainable Development Commission was axed and, while VAT for new build remains at 0%, VAT for refurbishment work will soon stand at 20%. Meanwhile the architectural press – to say nothing of Stirling shortlists past and present – concentrate on what is perceived as “real architecture”, leaving the B&Q brigade to deal with the boring work of refurb jobs.

Of course it doesn’t have to be like this. The client for Dow Jones’s latest project in Bath, Prospect House, had assumed previously that to get his elegant and efficient dream home he would have to demolish and rebuild the existing house he owned overlooking the city centre on Sion Hill. VAT disincentives and lower perceptions of upgrades simply reinforced this assumption and so it was only when tender prices for his proposed new build came back too high that he was propelled back to the drawing board. It proved to be a fortuitous turn of events.

The existing building was an eyesore unfortunately typical of Bath’s recent architecture

The existing building from 1985 had countless problems; it was poorly situated slap bang in the middle of the plot, atrociously planned such that the garden was accessed by passing through either utility room or bedroom and, to be honest, was an eyesore unfortunately typical of Bath’s recent architecture. Highlighting quite what a task we have ahead of us, the house was alarmingly only 25 years old but had minimal floor and roof insulation and no wall insulation at all. Dow Jones has turned all this around; the change in use, appearance and performance producing a house transformed and, to all but the initiated, seemingly contemporary through and through.

Key to this impression of newness is that, despite the all too evident conservatism of Bath City planning, the architect has been allowed to insulate the outside of the existing building envelope, increasing the U-value of the walls, for instance, from 1.38 W/m2K to 0.21 W/m2K. It is hard to disagree with the argument to improve environmental performance, yet the planners’ decision to allow this visually transformative approach seems in part at least an acceptance of planning sins past, most notably in the frankly revolting stone-ish blocks that formed the exterior cladding of the old house. It is a solution that surely won’t be deemed acceptable by planners up and down the country for the millions of red brick Victorian houses in need of thermal improvement, but in Bath the welcome result of Dow Jones’s approach was that there was no need to compromise on performance for fear of “shrinking” the house with internal insulation.

The 1980s house’s central location within its plot resulted in a series of external spaces that felt more like a leftover lot than deliberate garden, the steep slope of the site an unresolved inconvenience. The existing garage has been converted to form a new west-facing kitchen with east-facing skylight above, its angularity seemingly cocking a raised eyebrow toward the site entrance. To the west this has given purpose to the existing stepped topography with the formation of a series of terraces, the space directly outdoors transformed from utility yard to a concrete-floored extension of the internal cooking space.

To the east, and set apart from the house, sits a new building with garage on the upper level and studio workspace on the lower, the expected section of low ceilinged car space and generously formed studio flipped, allowing vehicular access at street level for the clients’ collection of sports cars, but also denoting in section both the possibility of additional double-decked car storage and the hierarchy of space appropriate to a man who loves his Porsche.

An awkward layout has been made light and spacious yet full of enjoyable incident

The space between the buildings offsets the site’s centrality in a considered manner, and the offset between the two facades orders the composition. Shared spaces were previously disconnected from the garden and the new layout has modified the existing low roof between the floors to form a south-facing balcony giving the living room outdoor space and access to the lower-level garden via a concrete stair, arriving purposefully between house and studio and providing tension and movement to the space separating old and new. It is a satisfying aspect of the development, and in general perhaps an underrated architectural enterprise, that an awkward layout has been sensibly reconfigured, becoming light and spacious yet full of enjoyable incident.

While the interiors are understated, defined by enlarged and re-positioned windows and a proper relation between rooms, the new exterior is altogether something else. The constructional logic of insulating, then over-cladding the existing house has been interpreted in a literal tectonic of wrapping; dark zinc forming a new continuous skin over the old walls and roof, solar thermal panels neatly tucked in. The metal appears taut; set-back guttering allowing a smooth transition from wall to roof, cloaked plinths suggesting the wall apparently touching the ground, and windows and doors set flush and toned to match the cladding, all tied together with a formal angularity born of the existing building and emphasised by the flush tectonic, yet carried through to the forms of the new garage and skylight.

Set against the darkness of the windows, handrails and zinc cladding, the paleness of the new concrete stair and terrace provides tonal relief, while the vertical rhythm of the standing seams, which provides an overall visual structure to the scheme is, together with the mullions and balustrades, contrasted with a tighter textural grain in the horizontals of concrete board mark and stair tread.

Between pragmatic internal re-ordering, the creation of deliberate garden spaces, immensely improved environmental performance and a completely new exterior which is thoroughly convincing in its architectonic re-imagining, the project presents a compelling case that refurbishment and retrofit need not be the domain of the faint-hearted.

The scheme is perhaps too high end to serve as prototype for the millions of buildings that need to follow. What it does present however is a rallying cry, a call that the solutions can be architectural, that intelligent planning of internal and external space is a valuable pursuit in creating homes for the long term, while environmental improvements can be both tectonically considered and an opportunity to make our environments more rather than less beautiful.

Hugh Strange is an architect based in London and the Hadspen Estate in Somerset

Project team

Architect Dow Jones Architects, Structural engineer Momentum, Quantity surveyor Cyril Smith, Lighting consultant Mindseye, Landscape design Alison Jenkins, Main contractor Emerys Of Bath


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