Number 1 Workbase

Workshop. Built in 1861 by Grissels, with later extensions and roof heightening. The building is constructed with a cast- and wrought-iron frame, brick infill between stanchions on the exterior, and corrugated iron cladding to the front and rear gables and roof. It has an L-plan, comprising a long range alongside No.2 dock and a 90-foot deep workshop range built at the head of the infilled No.1 dock. The gabled front has a double entry that is mostly glazed with thin vertical glazing bars below the roof line, with two glazing-bar sash windows to the left. The rear gable and left-hand return feature a row of glazed lights, above a row of mid-20th century casement windows with double doors to the left. The right-hand return has a row of fixed lights with small-pane casements. A range of similar construction alongside No.2 dock has brick facing to the dockside return.

The interior of the 5-bay front block shows I-section stanchions cast with brackets and wrought-iron trusses raised to the present height around 1886. The wrought-iron roof includes a traveller crane, still in situ in the range alongside No.2 dock.

This building is a highly significant survival within the context of both naval and commercial shipbuilding in the 19th century. It was built to house the forges and furnaces for the construction of HMS Achilles in No.2 dock. Achilles was the first iron ship built in the British naval yards, in response to the French navy's 'Gloire', and Chatham was chosen for its proximity to Thames-side shipyards. The building initially contained a furnace for heating armour plate and machinery for bending and planing processes. Drawings from May 1886 depict the intended roof heightening, which was likely carried out shortly afterwards.