Step House extension built around perforated birch-ply staircase

A staircase punctured with rectangle-shaped holes is the focal point of this two-storey extension Grey Griffiths Architects has added to a workers' cottage in west London.
The bespoke staircase allows light to pass from the original end-of-terrace workers' cottage into the extension, which Grey Griffiths Architects have aptly named Step House.Situated in the district of Wimbledon, the house originally had just two modest bedrooms. However its new owners – a couple with one young daughter a