3 St. James' Mews

This is a stone-built house with a scribed rendered finish and a Welsh slate roof, dating from the late 18th century. It has a street elevation featuring a one-window, two-storey and attic, gable-ended bay projecting to the left, and a symmetrical, one-plus-one-plus-three-plus-one window, two-storey range with hipped roofs over the advanced wings to the right. The windows are small-pane sashes, much of which have been restored; the main first-floor windows are tripartite, with a twelve-pane sash centrally positioned over what is believed to be the original main entrance. The gabled bay includes a six-over-six pane sash window in the attic, and paired twelve-pane sashes below. The ground floor sashes are replacements, restoring the appearance lost when the area was converted to a garage.

In 1926, the ground floor of the entire building was altered into a garage, with a showroom added to the street frontage and high, service bay doors inserted at each end. This conversion has since been reversed, restoring the building to a domestic appearance. A four-bay timber verandah with a classical frieze and cornice extends across the recessed central section. Beneath the verandah is a matching tripartite window and an angled, panelled door entrance squeezed into the corner alongside the advanced right-hand wing. Original forecourt railings with ball finials to square piers have been retained. The advanced wing on the right has garage doors leading through to St. James' Mews behind, and a tripartite sash window above. The left-hand gable features a bracketed cornice, a parapet, and high kneelers. The chimney stacks are roughcast brick and appear within the recently reslated roof.

The rear elevation is cement rendered and painted, with a cut-down chimney stack and modern replacement features. A Tudor window, noted in the 1991 listing description, was not observed during a resurvey.

The interior retains elements from a late Georgian remodelling. The main entrance originally led into a narrow central passage with reeded architraves and segmental arches, featuring six-panel doors. The rooms to the right have fine interiors, and a considerably earlier roof structure overall. The ground floor on the right side retains panelled shutters and ceiling cornices. One room has an older fireplace surround with broach stops and carved spandrels characteristic of Glamorganshire in the late 16th and early 17th centuries. The former garage bay on the right has transverse cross beams, one with a corbel. The main first-floor room has an unusual ceiling dating to around 1700. It features six wells, with outer quatrefoils having foliated corners, and a central pair of plain roundels, although its appearance has been somewhat altered by the insertion of a partition wall to create an additional room. A large room to the left has a three-well ceiling with a central rose. The roof comprises five bays of sufficient quality to suggest that it may originally have had trapped purlins, a relatively rare feature in Wales, although this could be a derivative of a Midlands clasped purlin rather than a true trapped purlin. The roof includes reused timbers and strengthening additions. A-frame construction is found in the roof of the right-hand wing, with massive purlins.