Looking down from an elevated position inside Number 1 Boiler Shop in Chatham Dockyard. The photographer is at the level of the overhead travelling crane looking towards one end of the building. The main part of the building has a double-pitched corrugated roof with a glazed section at the ridge, all supported by steel trusses. A double row of steel columns is along the centre of the space to support two overhead travellers. On the right is a single storey bay with a single pitch roof supported by large iron decorative frames.