With a series of stepped levels and angular windows, this extension to an Edwardian terraced house in South West London opens up to a leafy rear garden and optimizes natural light within the new living space. The design by Proctor and Shaw is called the Quarter Glass House, with the term ‘quarter glass’ referencing the custom-shaped triangular side windows on some vehicles.

The difference in grade between the existing ground floor house and the rear garden is 1.2 meters. To navigate this difference, the extension is designed as a sequence of stepped plateaus that descend slowly into the garden through a series of distinct kitchen, dining and outdoor terrace zones.

Maximizing natural light and window area, while still maintaining neighbouring residence’s privacy, the wrap-around L-shaped extension employs custom-made, angular windows which allow views to be best oriented with the surroundings.

The first and largest quarter glass window is positioned above the sliding doors to the garden, drawing in high-level light to the extension. A second quarter glass installation frames a cosy window seat that protrudes out into the garden. A third trapezoidal frameless window offers views into a newly created courtyard/lightwell space between the existing home and the new extension. The fourth quarter glass feature is a large triangular roof oculus set in deeply framed down stand beams.

The interior of the extension is warm and textured with muted copper and duck egg tones alongside a structural soffit ceiling of Douglas Fir and light grey floor tiles. The floor tiles continue from the interior of the space to the outside patio, highlighting a fluidity between indoors and out. At eye level, a seamless pale pink micro-cement finish is applied as a wall finish and backsplash and feature Douglas Fir floating timber shelves with integrated lighting line the length of the kitchen.

Keeping with the colour scheme, Ikea kitchen cabinetry was customised with light duck egg tone doors and drawers. This cost-effective specification allowed the clients to splash out on a custom copper-topped birch ply kitchen island, copper finishes for the sink, tap and utensil hung rails, along with a grey powder-coated aluminium framed dining table, which was custom designed by the architects.