Capel Mawr (Jerusalem Welsh Presbyterian Chapel) with attached school room

The chapel is built of roughly coursed rubble and slate roof with red tile cresting. The adjoining school room is brick. Entrance in gable facing street: pedimented gable with inscribed stone in the apex; paired 4-panelled doors with leaded overlights in moulded architraves in Tuscan portico porch, flanked by round-arched windows. 3 similar windows above, with keystones to heads. 4-bay return elevations have camber headed windows to ground floor, and round arched windows with stressed keystones above: all are small-paned with margin lights. In the rear gable wall, a later brick projection housing the organ is flanked by high-set round arched windows. The chapel is linked to the school room to its left by a hipped-roofed entrance block, with gabled porch flanked by 3-light mullioned and transomed windows. School range comprises 5-bay single storeyed hall, articulated by buttresses, with blue brick impost bands linking the round-arched windows. Gabled porch on inner face.

The body of the chapel is a wide space, with slightly inclined floor, 2 off-centre aisles and canted gallery round 3 sides. This has panelled balustrade and is carried on cast-iron columns with Corinthian capitals. Plaster ceiling divided into panels, with rosettes to light fittings and vents. Coloured glass window from entrance lobby into chapel. Wrought metal scrolled posts carry moulded rail enclosing set fawr; trefoiled panelled wood pulpit, with curved stairs with turned baluster rails to either side. Organ in arched recess to rear. Fittings include grained wood seating, and a wood low relief war memorial tablet; also one pictorial stained glass window of 1927, by Jones and Wallis. Other windows have coloured glass margin lights. Corridor with deacons' meeting room connects the chapel to the school room: a hall of 5 bays with glazed brick dado timber roof trusses, divided by a moveable screen from a smaller room to the rear.