Seion Fforest Calvinistic Methodist Chapel

Seion Fforest Calvinistic Methodist Chapel is a chapel built from coursed rock-faced sandstone in narrow courses, featuring flush sandstone dressings and a 20th-century concrete tile roof. The long wall at the front has two arched centre lights, two upper arched gallery lights, and two doors located in gabled porches, positioned between inner and outer windows. All windows are long and include stone voussoirs, rusticated jambs, and stone sills. The late 19th-century leaded glazing features unusual timber 2-light tracery, with the bars intersecting in ogee shapes at the heads. A plaque is situated above and between the centre windows. The porches are gabled, with stone voussoirs above the entrance arches and inset doors. The chapel has a raised plinth.

The left end wall contains a two-storey, two-window range of 16-pane horned sash windows, with paired brackets supporting the overhanging gable verges. The two-storey rear wall is made of rough rubble stone and also features 16-pane sash windows with stone voussoirs. The right end has a single-storey vestry with sash windows in the gable wall above the vestry.

Inside, there is a three-sided gallery supported by five iron columns, with a painted front that has curved angles, a deep cornice, and paired brackets. The brackets are located under arch-panelled pilasters that separate long horizontal panels. The top rail is moulded. The side and rear areas have painted grained box pews that are raked up under the galleries, while the centre block features pine pews with shaped bench ends and a similar three-sided set fawr.

A broad platform is situated in the centre of the entrance wall between two lobbies, with a solid pulpit front flanked by serpentine balustrades that curve back to balustraded stairs with ramped rails and slim turned newels. The frontal is panelled with inset bulbous columns at the angles, and the back wall of the platform is also panelled. Various marble plaques are present, including one from 1907 dedicated to the Rev William Davies of Neath, who was a pioneer of Methodism in the area and lived from 1727 to 1787. The galleries contain painted grained panel-backed pews and a panelled dado. The ceiling features a plain cornice and a central rose with an acanthus and laurel rim. The vestry has a boarded roof with iron ties.