Prospect House is located on Sion Hill, overlooking Bath. The house faces south and is built into a steeply sloping site with amazing views. It was built in the mid 1980s and conformed to the genre of houses built in Bath at that time: reconstituted Bath stone blockwork walls, a concrete tiled roof with big eaves overhangs, Proprietary softwood windows, and was trapped stylistically somewhere between volume house building and a nod to Frank Lloyd Wright.
The house was organized around an upper entrance level, with a living room, dining room, kitchen and garage; four bedrooms and a bathroom were situated on the lower ground level below. The typology of the house meant that only the bedrooms opened directly onto the garden, and the route from living accommodation to the garden was via the kitchen and the utility room.
The views which one would expect the house to exploit were somewhat disrupted by the ill-placed windows and the fact that their heads were at eye level, forcing you to duck to see the view on entering the room.
The location of the house in the very centre of the site and the ambiguous relationship it had to the geography of the site meant that the garden spaces felt a lot smaller than they actually are, and were mostly unusable.
The house is owned by a family with two teenage children. They had previously commissioned a scheme from an architect to demolish the house and build a new one in concrete and glass. However, the excessive costs of this project lead to it being stopped while the client re-assessed their options.
We were appointed to retrofit the house in a way that would realize the clients’ ambition to totally transform the character of the house and address the numerous architectural and technical failings of the existing building.
There were obvious organizational and functional problems with the house, as well as a host of technical and performance deficiencies, but the major architectural problem that had to be addressed was the way in which the building related to the topography.
The brief asked for a four bedroom house with a studio and a garage. It should make the most of the site and views, be as environmentally aware as is reasonably possible, deal with the insistent westerly winds that catch the house head on, and have a budget of £500,000.
Our strategy retained the existing form and structure of the house, with its inherent geometrical baldness, and stripped it of its extraneous detail. We repositioned and enlarged windows, reorganized the interior and locally adjusted the topography. The newly configured house was then wrapped with insulation and clothed entirely in chocolate brown zinc.
Adjacent to the house we built a new building, also dug into the slope of the site, that houses the studio at garden level and the garage at entrance level. This was located to exploit the location of the existing retaining wall that runs across the site and to create a range of new spaces that layer the threshold of the house.
The careful placement of this new building next to the existing house creates a sunken garden level courtyard, facing south, onto which the studio opens, and a ‘window’ between the two buildings at entrance level that frames a view across the valley towards English Combe, revealed as you walk down the drive towards the front door.
This new lower courtyard is made of powerfloated concrete and is a seamless extension of the studio floor. It is linked to the house via a sculptural, boardmarked concrete stair and rainwater storage butt which leads up to a new balcony that runs across the south elevation and connects the living rooms to the garden.
The main level of the house has been organized so that the living room faces south; it connect to the garden via the new balcony which has been built on top of the existing projection of the bedrooms below, and which was formerly a pitched roof. The floor of the living room level is oak, which runs outside to make the balcony decking.
The dining room has been placed on the west of the house so that supper is eaten with the dying sun projecting the shadows of the trees in the garden onto the dining room wall through a new, full height, sliding window.
The dining room is connected, enfilade, to the kitchen, which is located two steps down at garden level. The kitchen is formed by another powerfloated concrete slab that extends out of the house and runs across the garden as the upper level terrace of the garden. The kitchen opens onto the terrace via more sliding doors and seamlessly connects the house to the garden.
The location of the kitchen in the north-west corner of the house has been ameliorated by the addition of a large, projecting trapezoidal rooflight that faces east, and projects the morning sun onto the kitchen table.
The garden spaces have been reorganized as a series of useable terraces in either concrete or grass, and a new planting scheme is currently being implemented.
The house is now connected to the site physically, but also in terms of how the passage of the sun around the house is structured as experience. Inside and outside are one, and the newly relocated windows mean that previously denied views of the city are now available.
The existing external walls and the roof structure have been retained and the whole enclosed with 150mm of rigid insulation. This insulation is located above the roof deck which enables all ceilings to be removed. This, allied with the enlarged windows, makes the upper level of the house feel canopy-like, and emphasizes the treatment of the topography as the key element that reconnects this building to the place.
The standard details of the standing seam zinc cladding have been adapted to avoid the usual heavy eaves capping pieces that would otherwise destroy the idea of making a taught skin that emphasizes the material wholeness and the geometrical baldness of the building.
Similarly the windows, which are standard Velfac thermally broken system windows, have been adapted in such a way that they can be pushed to the front plane of the cladding, thereby making the external envelope read as a single taught façade. This has been done to avoid the zinc turning in to meet windows located in the centre of the opening, revealing its thickness and thus the fact that it is an addition to a pre-existing surface.
The performance of the house has been radically enhanced; U values have been improved from 1.38 to 0.21 for the walls and from 1.00 to 0.22 for the roof. This, along with the fitting of high performance windows and doors and a solar hot water system has already shown a dramatic decrease in gas consumption.
The radical position that this house demonstrates is that low energy retrofit and cutting edge architecture can be one and the same thing, and that environmental design does not need to be worn as a badge of honor. It also demonstrates that retrofit can drastically alter the character of a building and that demolition is not always the right answer.
Area: 350 m2
Cyril Smith Ltd
Names of other key consultants:
Lighting designer – Mindseye
Main contractor – Emerys
Building Design Magazine Architect of the Year Award - Refurbishment 2010, Winner
The Daily Telegraph Daily Telegraph Home Building and Renovating Award 2012, Highly Commended