Mantell Gwynedd

1 Castle Street and 20-22 High Street is a block of late Georgian houses built from brick, featuring a hipped graded-slate roof. There is a shared brick stack between numbers 20 and 22, and No 22 has an added skylight. The High Street elevation is nearly symmetrical on the first and second floors, with 12-pane hornless sash windows on the first floor and 9-pane windows above, while No 22 has 2-pane windows. The ground floor arrangement varies: No 20 has a doorway to the right with a replaced door but retains an overlight, and an altered 19th-century shop window to the left. No 22 features a late 19th-century public house front, framed by pilasters with fluted upper parts and foliage capitals, framing the shop window, along with a repainted panelled fascia and dentilled cornice. There are panelled doors on both sides with overlights, and the left-hand doorway now serves as the entrance to 24-26 High Street.

The Castle Street elevation is also balanced on the upper floors, consisting of a three-window range with 12 and 9-pane hornless sash windows, and a blind painted window in the left bay. The ground floor has a large 19th-century shop window with small-pane glazing, replacing a former doorway to the right, and there is a further blocked door on the left. No 1 features a panelled door with an overlight to the left, and a 12-pane hornless sash window above a blocked cellar opening.