LocationAuckland Road, Cambridge, England
ArchitectsAshworth Parkes Architects
From the architect. The site is very small measuring 7.5 metres wide by 10.5 metres deep, and is flanked by 3 metre high walls to the East and the North, and a 2 metre high wall to the West. The new house was not allowed to rise higher than the eaves of the house next door to the North. We were only allowed 1 metre squared of obscured window on the Southern elevation, no windows above the top of the wall on the Western elevation and 1 metre squared of window on the Northern elevation. We had to set the building back from the road, decreasing the usable space on the site even further.
Externally above the brick walls, the house is clad in a larch rain-screen, there is a grass and wildflower roof, and several roof-lights to mitigate the restriction on windows on three of the main elevations. The windows are set behind the rainscreen, which obscures their frames. The windows open inwards for ease of cleaning.
On the ground floor dug down 600mm, which gave us a floor to ceiling height of 2800mm. This makes a small space feel much more spacious and allows the natural light deeper into the floor plan. The change in level allows us to create underfloor storage at the entrance, any storage being at a premium in such a small house.
The first floor is cantilevered from large fair-faced concrete piers which also house the larder and the cloaks, as we were unable to bear any load on the existing brick walls, which were in a precarious state. There is a white resin floor as well as a white enameled staircase, again to raise the light levels inside.
The interior arranged around a double height space flanked on the first floor by a small study area. The related spaces are intricately connected, and although the spaces are small, there are various perceptions of depth. This is heightened by the use of mirrors and translucent meshes. Upstairs the three bedrooms, shower room and bathroom, each have a different character, provided by the varying fenestration. A key idea in the house was trying to create different spaces and little moments of interest that would again help to make the house feel larger than in fact it really is.
Working on a very tight budget, our aim was to design a house that from first principle would use as little energy as possible. We were not able to afford some of the more headline grabbing bits of kit, photovoltaics, heat exchangers etc., so all our environmental moves were intrinsic elements within the fabric and planning of the house.
Firstly, the house is very well insulated. On the first floor, which is timber framed, there is 200mm of sheep’s wool insulation within the walls and the roof. On the roof, we allowed for the additional loading of 200mm of soil to create a semi-intensive green roof. Both the roof and the sheep’s wool are hydrophilic and this means that they provide excellent insulation properties in both hot and cold conditions. The installation of this type of roof means that rate of rainwater run off from the roof is reduced dramatically.
Within the house, on the ground floor, is a lot of exposed thermal mass in the form of the large elements of fair-faced concrete, and the resin floor, that we use to moderate the building’s temperature.
The ground floor has an underfloor heating system, whilst the only heating of any form upstairs are the heated towel rails in the shower and bathrooms. The natural buoyancy of the hot air means that it rises up the double height space, into the first floor of the house and the levels of insulation means that the first floor of the house warms up very nicely without the need for any heating of its own.
Being stuck behind high walls and the number of windows being severely limited meant that we had to use roof-lights to maximize the daylight within the house. These coupled with the light bouncing up off the white resin floor, which is in effect a large light shelf, mean that the interior of the house is very bright. We have used a mirror next to the large roof-light in the double height space and this bounces light deeper into the floor plan.
The roof-lights are, coupled with the double height space, very useful in cooling the building in Summer. On hot days we open them up and open the French windows downstairs a small amount, which creates a stack effect through the house and drains the hot air out of the roof and pulls in pleasant cool air at a low level. The lack of windows on the Southern and Western elevations also limit any potential solar heat gain.