The London mews house, originally designed for the horse, carriage and driver, typically has no garden or windows at the rear. This mews house in Kensington was unusual in having a slim rear light well to serve the upper floors. To provide more natural light to the ground-floor living space, this light well was extended to the full width of the property and a glass floor installed at first-floor level to light the rear wall plane. The result is a dramatic backdrop to the main ground-floor living space. The overlooked windows to the master bedroom were removed and replaced with full-width, floor-to-ceiling glazing opening on to the light well. On the top floor, the light well was expanded to create a sunny external terrace connected to the sitting room.