House of Layers is a Grade II-listed Victorian house located in the London Borough of Islington, North London. Working within the constraints of the listed building - thought to date back to the 1840s - and its immediate surroundings in a conservation area, we provided the structural engineering design for a significant refurbishment and extension of the property which included re-levelling the floors, removing and relocating partitions, and designing a new feature stone staircase.
Working closely with The Stonemasonry Company and drawing on previous experience of designing post-tensioned stone structures, we designed the staircase to span from lower ground level up one storey.
Replacing a 1980s timber stair, the new arched structure was formed using solid reinforced stone from three individual pieces of Mirabelle Limestone. The separate pieces were pinned together at prominent, highly visible points displaying the craftmanship of the structure and the beauty of the stone dating back several million years ago. The decision to build in three sections rather than individual treads was triggered by the idea of allowing the grain of the stone to run uninterrupted.
The rustic stone contrasts with walnut timber furniture creating a warm and neutral pallet of textures and colours. The stone is used elsewhere in the refurbishment including the lintels, floor surfaces and wall surfaces.
Celebrating stone as the key architectural element of the project was driven by the ambition to create an honest and environmentally friendly design. Shaping much of our built environment, concrete accounts for approximately 8 percent of global carbon dioxide emissions. Our work focuses on rejecting the common and environmentally detrimental industrial process associated with mixing concrete to produce a composite material typically 3 times weaker than natural limestone and ten times more carbon intensive. By designing with raw stone, the stair stands as a stunning architectural centre piece and shows how the material can be utilised in small scale residential projects.
- AJ Retrofit Awards 2019 , House (£500,000 and over), shortlisted , 7 2019