Scenario were approached by a couple who had purchased a run down office building tucked behind a large red brick apartment block in a West Hampstead Conservation Area. The property had an extant planning permission for use as a house as well as to extend down to provide a new basement level. Our proposal builds on this to add a partial storey above and rethink the external envelope in order to accommodate the needs of a family of four.
The proposal is located on a tight backland site set back 34m from this building line. Given its lack of prominence and distance from the public highway, the site is ideally suited for a contemporary house which is minimal, lightweight yet durable. The basis for the design is the interaction between the needs of the client and the constraints of the site, most prominent of the latter being, the mediation of light and the management of views both in and out of the property.
The envelope is designed to optimise the environmental and visual performance of the spaces within. The existing building and granted basement extension include large areas of glazing, particularly facing East over the cricket field. These are retained in order to take advantage of all available natural light reaching the site.
The proposed massing takes advantage of the substantial difference in level between the street and the cricket ground (circa 3.5m) which allows accommodation of the lower level in such a way that is completely hidden from Crediton Hill. Consequently, despite an increase in floor of nearly 200m2 , the resulting structure above ground is only one storey plus the partial mezzanine.
The clients both spend a significant amount of time working from home. This meant that as well as living accommodation, the brief included workspace for each of them. This was provided in a partial mezzanine level sitting above the master bedroom. The tallest part of the volume containing this mezzanine was located along the Northern boundary which has an existing tall fence. This allowed for a generous double height space above the living room which maximises light levels and increases natural ventilation.
The ground floor houses an open plan kitchen, dining and living space with their connection to the outdoors maxmised through the use of carefully scrreened gareas of glass. The master suite sits to the north of this floor below the partial upper floor. The proposed basement houses two children’s bedrooms and a cinema/playspace, a guest bedroom with an ensuite as well as storage and services.
Mindful of the potential for poor privacy levels, perceived additional overlooking of users of the sports field and excessive solar gain, the proposal is wrapped with a system of thoughtfully designed bespoke louvre panels. These selectively mediate the relationship between the internal spaces and the outside. The vertical fins are finished in light grey and set up a regular unifying rhythm across the facade.
In contrast to the walls, the roof is largely solid, this solidity is exploited to introduce expanses of green roof which aid the sustainability levels of the project. This treatment reduces the impact of overhead sun, acts to attenuate any rainfall and increases opportunities for biodiversity.
The project also incorporates solar panels and an air source heat pump to reduce the electrical demand. The operable windows and skylights promote natural cross ventilation.