Cathays Methodist Church including Sunday School attached to rear.

Cathays Methodist Church, together with the attached Sunday School, was built in the 18th century in a Neo-classical style. The church features a towered facade fronting a rare basilican chapel with a clerestory. The building is constructed of coursed, rock-faced Pennant sandstone, with Bath stone window surrounds, dressings, and string courses, interspersed with red brick. The roof is slate, with a stepped-pitch over the main building.

The front of the church is tall and imposing, with gables, originally featuring openwork cupolas to the domed roofs of the stair towers. The central entrance is now obscured by a later vestibule; above this are twin, round-headed windows on the first floor, and a circular window with simple tracery within a pediment. Flanking the main facade are projecting stair towers, each finished with a pediment and containing a round-headed doorway on the lower floor and a round-headed window framed between pilasters on the upper floor. The side elevations of the stair towers incorporate two small round-headed windows at the lower floor, reflecting the stairs inside. The chapel’s side elevation is divided into five bays by pilasters and features tall, round-headed windows with stepped yellow brick surrounds. Small, round-headed windows, with Bath stone surrounds, are grouped in threes at clerestory level. The front elevation of the Sunday School is in three bays, with gabled end bays featuring slightly pointed windows with Perp tracery. The centre bay is flat-topped with two doorways, and above, a couple of slightly pointed windows.

The original chapel space was divided vertically into two separate rooms. The lower room retains gallery balustrading – previously varnished wood-work, now painted – on all four sides, supported on round, cast-iron ground-floor columns with Tuscan capitals. The upper room retains round, cast-iron columns at the former gallery level, with composite capitals and semi-circular linking arches between the columns. The raised centre section of the roof features a flat, boarded ceiling and round-headed clerestory windows in triplets. Two ceiling ventilators have been replaced with flat panels. The ceilings to the aisles are supported on simple triangular, wooden trusses. A large organ by Harrison and Harrison of Durham, dating from before 1914, is housed in a grand, semi-circular recess behind a modern pulpit. The chapel originally contained pews for 850 people. The room below the original chapel contains round cast-iron columns and is partitioned into smaller rooms.