20, Saint Marys Street

No. 20 Saint Mary's Street is a house dating from the late 16th or 17th century, which was remodeled in the early 19th century. It features a rendered timber frame on a tall plinth, with some parts rebuilt in painted brick, and has a slate roof. The building consists of two framed bays and is designed in a Gothick style. It has one storey and an attic above a semi-basement, with an external brick end stack on the right side.

The exterior includes a pair of large gabled eaves dormers, each containing a two-light Gothick wooden casement window with Y-tracery. On the ground floor, there is a three-light Gothick wooden casement window to the right with intersecting tracery, and a 16-pane glazing bar sash window to the left. The central section features a two-light wooden Gothick window with Y-tracery on both the ground and first floors. Below this is a central six-panelled door, with the lower two panels beaded flush and the upper panels shaped, raised, and fielded, surrounded by a moulded architrave. The entrance is approached by a flight of external steps with railings. There is also a three-light basement window to the right, and the right-hand gable end has a two-light attic wooden casement window to the left and a blocked small circular window to the right. A 20th-century brick lean-to is present as well.

Inside, the entrance hall features a moulded cornice. The early 19th-century staircase includes winders, a closed string, stick balusters, and tapered square newel posts. The right-hand ground-floor room has a moulded cornice, while the left-hand bedroom contains an 18th-century door with two raised and fielded panels. In the right-hand basement room, which was likely the former kitchen, there is a fireplace with a probably reused late 16th or early 17th-century moulded wooden lintel.