25, Gloucester Street

25 Gloucester Street is a house that has been converted into an auction room and a flat. It dates from the late 18th century to early 19th century, with origins that trace back to the late medieval period. The building is constructed of coursed squared limestone rubble and features a Welsh slate roof. There is a brick stack at the right end, which is shared with No. 27 Gloucester Street.

At the rear, there is a very large 20th-century extension that serves as the auction room and gallery, while the front range contains offices and the flat. The front of the building has a two-storey, three-window layout. On the first floor, there are three 19th-century two-light timber casements with stone cills. The ground floor features two 19th-century 2/2-pane horned sashes, also with stone cills. To the right, there is a pair of half-glazed 20th-century doors, and to the left, a deeply recessed 20th-century six-panel door.

Inside, the building has undergone significant alterations in the 20th century. It has a three-bay butt-purlin roof with heavy smoke-blackened principals, which may date back to the 15th or 16th century. This roof has also been altered but retains its ridge plate and some early rafters, although the collars have been removed.