Banishing the shadows from a narrow mews house in London's Chelsea required a radical internal rethink from Azman Owens Architects.
The three-storey building suffered from a dingy cellular layout, with little light delivered by the windows on the narrow street front and even less arriving from the rear. But finding ways to draw light into the darkest areas was complicated by the borough's tough planning department.

Changes to the building's shell were outlawed early on, which meant that work was largely restricted to the interior. The initial move was to gut the building completely and so lose the partition walls and space-hogging staircase. "Before we started, the place was organised so poorly, with poky little rooms and a kitchen pushed to the back of the basement," says architect Joyce Owens. "It was just easier to start over again." The redesign kept the basic three-floor arrangement, but the demolition work gave the architect the freedom to develop two channels of space opening out from the front entrance. These start at the door and then move in opposite directions. The first is a narrowed and airy staircase heading up towards the roof; the second a strip stretching horizontally along the ground floor.

According to Owens, trapping light in the stairwell was the project's "big idea". Open, oak stair treads are supported by an inconspicuous, mild steel frame, with a gap left between staircase and white-painted wall. Light has been reintroduced by punching a wide ceiling window through the roof. Running next to the stairs and emphasising the vertical thrust is a free-standing bookcase that rises through all three floors. Solid shelves of American cherrywood contrast with delicate steel wires in such a sculptural way that the client has decided to keep it bookless.

The other spatial axis, which runs along the ground floor, was previously the dark heart of the house. Main contractor Varbud Construction cleared the space of superfluous walls, leaving the architect an open area from the front door to a mini-courtyard at the rear of the house.

To keep the axis unbroken, the office and bathroom are set back on either side of the main visual line. Portuguese limestone flooring is used across the entire area, while light filters down from strategically placed cavities in the ceiling. This is a tactic used throughout the house, the idea being "that one room borrows light from another", says Owens.

Despite a perpetual struggle with the council's planners over detailing – it was originally hoped that the entire roof of the first-floor kitchen would be glazed and there were problems with angling a patio at the back – the final work is an impressive example of problem-solving. The planning limitations also reined in the costs, which came in at a mere £130,000. As Owens puts it: "It's pretty reasonable for what is practically a new house."

Under £1m