Sometime in the past the owners of a typical early-Victorian house in north London decided to make a bit more room in the basement. Extraordinary as it may seem, they did this by neatly slicing the foundation corbelling at the bottom of the party walls and digging out the space. Prior to this, someone else had added an extra storey and a shop at street level. The neighbours on either side were active too, contributing, at different times, extensions which increased loads on the undermined party walls.
This haphazard history of construction and intervention was instrumental in dictating the approach of DRDH Architects to a brief from the new owner, an artist, to develop the house as a living and studio space. The owner wanted to open up the building, creating a clear relationship between the new and found spaces in the lower half of the building. The project was designed in 1999 but construction did not start until 2004. It was eventually funded by separating out a two-floor maisonette in the rooms at the top of the house, to be refurbished separately for sale or let. The focus for the designers was the client's own retained space - compressed into a number of small dark cellular areas in the basement, ground and first floors - which needed to be redefined to create the intended open spaces in the re-established house.
'The immediate concern was to structurally stabilise the building, ' says Daniel Rosbottom of DRDH Architects. 'We cast a holding foundation at the outset, a triangular piece of concrete that replaced the missing corbels. The new foundation grew through the course of the design process to become a physical entity in its own right. Expressed as a vertical concrete element, it rises through all spaces on the three levels, an armature that frames the newly created areas.' At basement level the massive concrete volume offers the means to work, providing library space, a desk and storage. At ground level the monolithic structure defines separation between the house and the corridor which provides access to the existing stair, leading to the flat above - it facilitates this through the formation of a precise concrete stair linking living and sleeping spaces. The concrete form continues to the first fl oor, where it defines the bathroom space and offers a deep step to an external terrace.
'Each floor in the house is a sequence of connected spaces at varying levels. The concrete element allows this to happen not only programmatically but also structurally, ' says Rosbottom.
Structural engineer Mervyn Rodrigues developed this with the architect, allowing the concrete to pick up part of the load of the party walls at first-floor level and transfer it onto six new mini piles at basement level. This new loadbearing structure allowed the removal of existing cross walls which had until then braced the party walls. This meant that the house could be opened up from front to back, with a double-height space introduced against the street to allow natural light into the studio.
'The contractor, Jonathan Jackson, is really a cabinet maker, so all the timber formwork was very accurately made.
You can follow the shutter lines left in the concrete with precision, although the material quality is very raw' says Rosbottom. The use of Douglas fir for floors, stairs to the basement and furniture continues the consistent relationship between timber and concrete across the entire volume of the house. Part of the timber lining folds to become a door which connects to a small balcony that is carved out of the concrete and overlooks the double-height space of the studio.
With 18mm Douglas fir ply used to form the furniture in the living space, the actual wood and a memory of wood resonate through the whole interior. And existing party walls were stripped of their finishes and painted in a traditional limewash, revealing the ghosts of found surfaces and the marks and scars of previous interventions inside the house.