31, Castlegate

31 Castlegate is an office building, now a restaurant, constructed between 1825 and 1826. It was designed by PF Robinson and GT Andrews for their own use. The front is made of orange brick in Flemish bond, with English garden wall bond on the right side. It features overhanging boarded eaves and brick stacks on a slate hipped roof.

The exterior has a raised ground floor on a semi-basement, with a two-bay front facing Castlegate. There is a renewed six-panel door in the basement to the left, and on the ground floor to the right, there is a 12-pane sash window with a painted stone sill and a flat arch of gauged brick. The rear has altered openings in the basement, and there are two 12-pane sash windows on the upper floor. The right return has five bays, with a gabled round-arched porch that projects in the center, featuring a renewed six-panel door and a divided overlight. In the basement, there are small-pane windows with segmental arches, including a 2x6-pane horizontal sliding sash window to the left of the door. Full-height external shouldered stacks are located in the bays flanking the entrance.

Inside, there are reset late 18th-century chimneypieces in the ground floor rooms, which were formerly drawing offices. The larger room has a fireplace with fluted pilaster jambs and acanthus capitals, a frieze with moulded urn and leaf motifs, and an enriched cornice shelf; the replacement grate has late 19th-century tiled slips. The smaller room features a fireplace with tapered fluted pilaster jambs and a moulded enriched frieze with composition urns and a plain center block.

Historically, plans submitted by PF Robinson and GT Andrews for remodeling the adjacent York Castle were accepted in 1825 and executed between 1826 and 1835, after which the castle was demolished. This building served as Andrews' office until his death in 1855 and was used by successive partners in the practice until 1891. It is likely the earliest surviving purpose-built architects' office.