Groeswen Chapel

Groeswen Chapel is a Classical-style building dating from the 18th century. It is constructed of coursed rubble stone, rendered to the rear and sides, with ashlar dressings, and a 20th-century pantile roof. The front facade features a three-bay gable end with an open pedimented gable containing a large glorification arch. Long and short quoins accentuate the front, finished with an urn and obelisk finial. Round-headed openings are embellished with vermiculated keystones and impost capitals. The arched doorway, bearing the incised date 1742, contains double panelled doors. Above the doorway is a stepped triple-light window with a bracket sill and ogee tracery to the central light. A scrollwork panel above the window reads 'Y groes wen'. A quatrefoil sits beneath the glorification arch. The outer bays have tall windows with original glazing bars.

A two-storey section with two windows is attached to the east wall, featuring round-arched, horned four-pane sash windows. A pair of tall narrow arched windows are located to the rear. An adjoining two-storey vestry, to the right, is cement-rendered with a slate roof and a west-end stack. A central lean-to porch, with a staircase on the left providing access to the first-floor doorway, is present. The entrance is flanked by 20th-century windows. There are two 20th-century ground floor doors, half-lit and partly boarded, along with stone mounting steps to the right. The rear of the vestry features three windows to the upper storey and three small, irregular windows to the lower storey, all dating to the 20th century.

The chapel and vestry are enclosed within a railed forecourt, which leads to a large burial ground with a collection of 19th and 20th-century monuments.

Inside, an entrance vestibule features stairs to the left and right that lead to a gallery. Boarded doors lead into the chapel, between which is a square window with wooden diamond glazing bars and coloured margin glazing. A three-sided gallery is supported by narrow cast iron columns with foliate capitals. The gallery front is panelled and decorated, incorporating a clock displaying "Barry/Cardiff.” A polygonal pulpit stands within a round-headed archway of moulded and decorated plaster. Behind the arch is a bronze plaque featuring a portrait in relief of William Edwards, accompanied by an inscription commemorating his role as the self-taught engineer and builder of the bridge over the River Taff at Pontypridd, and as the church's first minister for 40 years. The work, dated 1906, is by Goscombe John. Stained glass in red and blue is set within the windows flanking the arch. The ceiling is boarded, with an ornate plaster ceiling rose. The chapel has three banks of box pews with circular heads to the pew ends, and three tiers of pews leading to the gallery.

The upper storey of the vestry includes a planked door and wainscot panelling. A late 20th-century fireplace is located at the west end.