18, St Mary Street

House at 18 St Mary Street, Chippenham

An important early 18th-century refronting of a late medieval property that retains substantial evidence of its earlier timber-framed construction and complex historical development.

The building originated as timber-frame, now exposed only on the right-return wall where close studding with a middle rail survives. The main front is rendered limestone rubble with ashlar quoins, with some 19th-century brick to the rear. The roof is slated with a parapet and ashlar stacks.

The plan comprises a 4-unit front range, originally timber-framed and heightened by one storey in the early 18th century. The rear right range creates an L-shaped footprint, with an originally-jettied 3-bay range to the front including workshops and warehousing in the upper floors. This is interrupted by a bay roofed at right angles, leading to a further 3 bays to the rear. These two right-angled bays are all that remain of a rear range which, parallel to the front and adjacent to a left-hand jettied range, once enclosed a courtyard.

The exterior presents 3 storeys with a virtually symmetrical 7-window range. Features include a moulded cornice and string courses between floors, a parapet, and a plinth. Six of the windows are 6-pane sashes in forward frames, paired to the left of centre. The centrepiece is a stone doorcase with engaged Tuscan columns, cornice, entablature and pediment, with steps leading to a recessed panelled door with raised and fielded panels. Adjoining the rear right wing is a reset 14th-century pier with moulded capital.

The interior of the front range retains early timber-frame, mostly obscured by later work, though one exposed 16th-century chamfered beam survives on the ground floor. Much original 18th-century joinery remains, including early 18th-century bolection-moulded panelling with box cornicing and original shuttering, and 1770s reeded and Greek key dados. Two ground floor rooms feature unusual cornicing arrangements enclosing two small square areas, the right-hand hall possibly serving an original lightwell. A late 18th-century neoclassical hob grate decorates the first floor left room, and an early 18th-century moulded architrave frames the first floor right fireplace.

The short rear left wing, dating from the early 16th century, was mostly demolished and rebuilt in 1994, but retains a 16th-century stone fireplace and surviving timber-frame evidence of its originally jettied construction. The 3-bay rear right wing dates from the late 16th century and features an interesting roof with in-line butt purlins and collar trusses with windbraces and queen posts morticed into bridging beams. The deliberate omission of tie beams to facilitate working headroom, combined with a line of originally shuttered windows beneath the eaves, indicates this area's former use as warehouse or workshop space. The ground floor room retains early 18th-century fielded panelling.

The two bays to the rear, roofed at right angles and forming the surviving part of a range that originally enclosed the courtyard, contain much reset medieval framing, mostly smoke-blackened. A 3-bay range to the rear also features smoke-blackened trusses with threaded ridge purlins.

This represents an interesting and significant surviving example of a 15th and 16th-century large merchant's house, including warehouse and workshop accommodation. The 18th-century work, particularly the internal joinery, makes an important contribution to the property's architectural interest. A detailed record of the complex building history would be of considerable value.