The principal brief was to redefine the relationship from grand home to beautiful garden whilst delivering a new social hub that was appropriate for this splendid 4-storey Victorian town house. Our design proposal was to create a new light-filled room that blurs the threshold of inside to outside and mediates a new relationship with the beautiful garden and grandiose parkland setting beyond. Simplicity of form and a bold approach to materiality create an elegant but dramatic black brick-clad extension that draws on the original brick detailing of the house.
The project is in a Conversation Area and took a challenging journey through planning, including an Appeal, which resulted in additional massing being constrained to the Lower Ground Floor only. The extension is therefore low and discreet within its wider parkland setting, preserving the rear elevational views of this row of grand houses enjoyed from the sloped park behind. Sectional height was also constrained by the grand traditional sash window overlooking the garden from the upstairs double reception room. It was important for us and our clients that this wonderful original feature was retained and enhanced.
In order to bring generosity back to the lower ground floor spaces, the back wall of the house was removed and the lower ground floor plane excavated down as low as possible whilst avoiding internal underpinning. A new heated structural slab was replaced throughout for improved comfort. The slab continues externally to create a semi-submerged courtyard space that captures the southerly light whilst retaining privacy. Retaining walls with integral planters bring the garden greenery cascading down to the new courtyard space.
The reconfigured lower ground floor plan is arranged with a ‘core’ of secondary supporting functions, including circulation, utility room, shower room and plant, around which a grand L-shaped room is wrapped housing living, kitchen, dining and snug. The new kitchen is placed centrally in the plan serving the surrounding social spaces. Two sitting spaces, one cosy orientated around an original fireplace, one which opens out to the garden, offer a variety of opportunities for relaxation depending on the time of day or season.
The new extension roof is conceived as a bold horizontal plane articulated with a linear matt black soldier course brick lintel that wraps around a cantilevered glazed corner. The thick floating roof edge is both heavy and light at the same time, carrying the weight of a lush sedum lawn and oversized roof light above, but effortlessly suspended above thin framed large format glazing with-in a column-free span. The glazing line is set back with a generous overhanging brick soffit in order to provide solar shading, and reinforce the horizontality of the roof.
The roof structure was technically challenging to detail and co-ordinate whilst retaining as much thinness as possible. The Nexus® system by Ibstock was used to secure the external brick soffit. This was carefully coordinated with the rear steel whose depth, determined by the column-free span, was the defining factor in the thickness of the slab-like roof. To the underside, glazing frames, lighting tracks and curtain rails were all recessed flush. Above the tightly packed insulation the weather proofing layers were intricately set out to ensure drainage falls worked with flush cappings and existing window cill levels. The highly insulated roof is finished in a lush green sedum system that extends the ecological footprint of the garden, whilst also improving the thermal and acoustical properties of the extension.
Top light and sky views are enjoyed over the dining area through an oversized 3.5m x 2.4m solar glass single-piece roof light. The positioning of the roof light reflects the dimensions and presence of the grand traditional rear window overlooking the garden from the upstairs reception room.