Castle House (Co-Op Store)

Castle House is a Co-operative department store built in 1964 to designs by George S Hay, Chief Architect for the Co-operative Wholesale Society, with interior design by Stanley Layland, interior designer for the Co-operative Wholesale Society. The building is of reinforced concrete construction, clad with Blue Pearl granite tiles and veneers, grey granite tiles and veneers, buff granite blocks, glass, and brick.

The store occupies a roughly rectangular site with a massively splayed corner facing the junction of Angel Street and Castle Street. It contains four sales floors with a top floor accommodating a restaurant, offices including the board room, and staff canteen. Sales floors occupy the front of the store, accessed by a central spiral staircase with passenger lifts to the rear and two outer staircases, each with a passenger lift. The staff entrance, staircase and passenger lift, three loading bays, and service lifts are located at the rear of the building.

The main elevations on Angel Street and Castle Street are blind to the first and second sales floors, faced in a band of square polished tiles of Blue Pearl Cornish granite. Modern signage appears on the splay, with upper left Co-op and Post Office signs, a central banner sign, and to the right a Co-op sign and digital clock. The ground floor of the Castle Street elevation has four plate glass windows lighting the supermarket, separated by piers of rock-faced buff granite blocks laid in stretcher bond, edged by veneers of Blue Pearl granite, with shallow grey granite stall risers. A window and double doorway are positioned to the left, fitted with modern glazed and metal doors, all beneath a zig-zag edged concrete canopy. Five similar plate glass windows appear on the corner splay with a zig-zag edged concrete canopy. To the right is the position of the former wide recessed entrance doorway, now a display window. An inserted doorway appears to the left of the Angel Street elevation with a plate glass window to the right.

The top floor is deeply recessed under very deep eaves with indented hexagon shapes to the soffits. Wide aluminium-framed windows appear throughout, with those on the Castle Street elevation featuring inset square pivoting casements. A doorway opens onto a shallow, full-length balcony. The terminating stair tower on Castle Street is faced in square polished tiles of grey granite, with routed vertical lines of darker granite to the left of the stair window. The vertical stair window consists of alternating plate glass, horizontal beams, and textured panels. The zig-zag edged canopy continues over the ground-floor entrance, and to the right of the doorway stands a single tapering piloti covered in grey-blue tesserae. Modern sliding glazed and metal doors provide access. The Angel Street elevation terminates in an angled glass curtain wall containing the stairwell, with anodised aluminium frames to the glass panes. A continuous rail is fixed to the overhanging eaves with a permanent window cleaner's hoist.

The rear elevation, reached from King Street, is of brick in Flemish bond with a deep flush plinth of dark grey bricks and a slightly recessed stairwell incorporating the staff entrance. This section is faced in rectangular, textured concrete tiles with diagonally placed square windows lighting the stairs. The staff entrance is set beneath a shallow concrete canopy, with a glazed metal double door to the left of a glass brick wall incorporating glass ventilators. To the left, a glazed curtain wall rises to the top storey, with a partial external fire escape. Beneath this is a row of square single-pane, central pivoting windows. At lower level, a vertical single-pane window is flanked by two square windows, with two square windows set one above the other. To the right, a plant room with ventilators occupies the top storey. The ground floor has a single loading bay with paired loading bays to the right. Above are three storeys of windows: similar square, single pane windows set in pairs, and two horizontal metal-framed windows to the two upper storeys over the left loading bay. To the left is a return curtain wall with a loading bay on the ground floor and four storeys above of alternating concrete panels and glazing. The east side wall is blind. On the roof is the reinforced concrete restaurant roof, suspended from two external, inverted U-shaped beams of 50 tons each.

The central spiral staircase and two outer staircases rise the full height of the building. The free-standing spiral stair is made of reinforced concrete with terrazzo finish, featuring slightly angled stainless steel balusters and a double handrail of timber with a higher plastic-coated handrail. At the top of the staircase is a relief mural representing a cockerel and fish made of aluminium, copper and metal rod, with red French glass for the fish's eye and cockerel's comb. The mural is displayed on a backdrop of orange-coloured Japanese grass cloth. The stair is lit by a shallow concrete dome set with circular glass bricks. To the rear of the spiral stair on each floor is a curved wall faced in light and dark grey veined granite veneer, with two lifts and a central clock. Above is a curved, leaf-shaped canopy mirrored by similarly shaped terrazzo flooring with hexagonal patterning. The curved wall on the lower ground floor is now covered by modern green plastic sheeting.

The Castle Street and Angel Street staircases have open wells with a landing on each floor and a lift to the rear. These reinforced concrete stairs have terrazzo finish and similar balusters and handrails to the spiral stair. The Castle Street staircase has grey veined marble facing the lift shaft, and the wall is tiled with tiles by Carter & Co in a linear abstract pattern. The Angel Street staircase has wall tiles in abstract spot patterns by Carter & Co to the outer side wall and lift shaft. The inner side wall has a series of thin, vertical recessed panels of stained glass. Some original light shades remain of tubular white glass with copper bands. The end wall to Angel Street is faced to the interior with rock-faced buff granite blocks laid in stretcher bond. A bronze opening plaque and Post Office War Memorial plaque are mounted here. An inserted doorway provides access through to the adjacent Hadfield Cawkwell & Davidson block. The staff staircase rises round a central lift shaft. Steps have terrazzo finish, walls are lined with yellow tiles in stretcher bond, with similar pale green tiles to the lift shaft.

The board room on the top floor is set at the end of a corridor off which are a series of executive offices. The room has canted inner corners echoing the horse-shoe shape of the suspended timber lighting canopy over the table. Walls are panelled with thin, slightly curved, vertical strips with a darker horizontal band at dado level, except for the long inner wall which has hidden pivoting doors concealing a cupboard. The door is leather padded to the interior, with an un-panelled central recess to its right where the dado band continues across the front of a series of inbuilt small drawers with opening cut-outs. Doors opening off the corridor have routed timber surrounds. Offices are timber panelled, with lighter vertical panelling with darker band at dado height, inbuilt cupboards with flush panelled doors, recessed niches with inbuilt drawers continuing the dado band, and inbuilt cupboards beneath windows with glass sliding doors.

The restaurant on the top floor has a ceiling structure of inverted pyramids of acoustic plaster. Original features include terrazzo flooring with hexagonal patterns, acoustic ceiling tiles, terrazzo partitions and modesty screens to washrooms, and timber and glazed double doors, those on the top floor with square handles of thick blue glass, and glazed timber screens between the Castle Street staircase and sales floors.

The Brightside and Carbrook Co-operative Society was formed in 1868. In 1914 it purchased land on Exchange Street for the building of central stores and offices. Due to the onset of the First World War, construction was not begun until 1927, at which point the remains of Sheffield Castle were discovered as the foundations were dug. The building was finally completed in 1938 only to be destroyed in the Sheffield Blitz on 13 and 14 December 1940. Sheffield Corporation compulsorily purchased the site, so the Co-op moved to the Angel Street and Castle Street corner site, initially with a single-storey temporary shop. Early in 1959 planning permission was granted for a new headquarters building. The new building was designed by George S Hay with a blind wall to the first and second sales floors, the inspiration being Sears Roebuck's Chicago store at Irving Park from 1933 and an un-named department store in Amsterdam. The suspended restaurant ceiling was the second such roof in Europe. The staircase relief mural and interior design was the work of Stanley Layland. The official opening was on 13 May 1964. The shop cost £925,000 including shop fittings.