Like numbers 6?8 (NPRNs 19371 and 413636) to the north and numbers 20?23 at the southern end of the square (NPRN 19375), the top two storeys of Perch Buildings likely demonstrate the original architectural design of Mount Stuart Square (NPRN 400316), with distinctive second-storey Venetian windows articulated by Doric pilasters and decorated with a stucco shell in the central arch. Originally built as a domestic building in c.1858 to the design of Alexander Roos, architect to the Bute Estate, it was later converted for commercial use, and in 1889 the first storey facade was heavily remodelled by W. D. Blessley.

The Francois Premier-style Bath stone first storey has a left-hand doorway to the right of which is a broad three-light window, articulated by bulbous columns with volute capitals. In the centre of each window is an exaggerated keystone supporting an entablature which runs the width of the building, the central keystone featuring a lion head. Under each window is a decorated panel. To the right of the windows is a pilaster also supporting the entablature, decorated with a cherub. The doorway is flanked by pilasters with swagged capitals decorated with lion (left) and human (right) heads. These support heavy brackets supporting the entablature, which is advanced over the doorway. The entablature above the door is surmounted by a small pediment above a panel bearing the date `1889?. There is a fanlight above the door above the centre of which is a small cartouche. Above the windows are the words `Perch Buildings?. The building is named after the coal owner Sir William Perch, who took over the premise in 1914.

(Sources: Cadw Listed Buildings Database; Victorian Society Tour Notes, VS01/16; Dowsett, McKee and Thorp, `Perch Building, Mount Stuart Square, Cardiff, WSP/40/17; Newman, Buildings of Wales: Glamorgan (London: 1995), 271)
A.N. Coward, RCAHMW, 05.07.2018