Bastion Arts Foundation

The foundation owned a corner plot with a nineteenth-century bastion wall running through it, listed, immovable, and exactly where a lobby would want to be. So the lobby went under the wall and the galleries went over it, cantilevered eight metres clear on two concrete blades.

The upper box is deliberately blind. Works in the collection are light-sensitive and the trustees wanted no daylight at all; we gave them a coffered roof carrying north-facing slots that can be shuttered individually, which satisfied the conservator and kept the rooms from feeling like a bunker.

The plinth is new masonry laid in the same coursing as the bastion, but set back forty millimetres so the join reads as a shadow rather than a pretence.