Dowlais Chambers was erected in the late-1880s on the former site of the Dowlais Inn. It is a large building four storeys with attics and eight bays. The first three storeys are of brick with a timber-framed fourth storey, above which is a series of shed dormers and tall brick chimneys in a hipped roof. The bays are articulated by massive brick pilasters.

The modern division of the building into Bay Chambers to the north and Dowlais Arcade to the south is reflective of the architecture of the building. The northern 3+1 bays have a large central entrance with segmental fanlight in an arched aedicule with decorated keystone and spandrels above with is a frieze decorated with cherubs and vase in relief. Massive brackets to either side support a balustrade. The central second-storey window has a decorated frieze and cornice. The bays to either side of this entrance have two pairs of vertical square-headed windows above blank panels. Above are large second-storey canted oriel windows with hipped roofs. The northernmost bay has a single pair of first-storey windows with a canted bay window of three shortened storeys above. The southern half of the building consists of 3+1 narrower bays. The central entrance is narrower but similar in style to the northern entrance, but with a pediment above rather than a balustrade. To the right is another very narrow door, likely replacing an earlier window. The windows are also similar to those in the northern half of the building, but single rather than paired. The southernmost bay contains the large arched entrance to Mount Stuart Arcade, which was built contemporary with this building to connect West Bute Street and Mount Stuart Square, resulting in the alteration of number 7 Mount Stuart Square behind (NPRN 19371).

(Sources: Victorian Society Tour Notes, VS01/16)
A.N. Coward, RCAHMW, 13.07.2018