Exterior
Early Decorated style chapel, its exterior strongly resembling a parish church with lofty nave, NW tower and spire, shallow transepts, lower and narrower chancel (housing an organ), and hall and Sunday School on the S and E sides. Of coursed rock-faced Pennant sandstone, Bath stone dressings, and slate roof behind coped gables.
The asymmetrical W front has flanking stair towers to the gallery, of which the S is 2 stages while the N is taller and carries the lofty spire. The W doorway is modelled on the W door of Tintern Abbey. Two doorways are set within an outer arch, which has 3 orders of nook shafts, foliage capitals and moulded arch. The doorways have a single central shaft and cusped heads, while the tympanum of the outer arch has blind tracery incorporating cusped circles against a diaper-work back surface. Each doorway has double doors with vertical ribs. The doorway is flanked by 2-light windows with impost bands carried over as a hood mould, and foundation stones below the sills. The 5-light W window, said to have been modelled on a window in Melrose Abbey, has a sill band and crocketed ogee gable, with hood and head stops. An angle buttress to the R side has a gabled cap with blind arcading, and polygonal pinnacle. On the R (S) side is a 2-stage stair tower, with angle buttresses, and hipped roof behind a plain parapet incorporating blind arcading to the abutment with the main chapel. Its W doorway has a pointed arch with continuous moulding, double doors with vertical ribs, above which is a 3-light landing window with sill band. On the S side of the tower is a cusped light with hood and foliage stop, above which is a 3-light landing window with sill band.
The N side of the W front has a 3-stage tower, incorporating gallery stairs, with a tall parapet spire. It has angle buttresses with gabled offset to the lower stage. A projecting doorway is under a gabled hood. It has 3 orders of shafts with foliage capitals, a finely moulded arch with cusped inner order, and double ribbed doors. A hood mould has foliage stops. A cusped roundel beneath the apex has radiating blind tracery. The N side has a 2-light window with hood mould and impost band, above which is a small cusped light with hood mould lighting the stair. The middle stage has a sill band, and each face has a 5-bay arcade with shafts and foliage capitals to cusped arches. The outer bays are blind, the 3 inner bays have narrow lancet windows. The buttresses have gabled offsets to this stage. The tall bell stage has 2 2-light windows with ringed shafts and foliage capitals, and louvres, inset with raked sills. Diaper work is over the windows and then the parapet has blind arcading and coping. The buttresses are crowned by broad polygonal pinnacles with spirelets. The octagonal parapet spire has 2-light lucarnes in the cardinal directions. Red sandstone bands incorporate small roundels and string course with gabled hoods.
The N side, facing Marlborough Road, is 4 buttressed bays with 3-light windows, of which the 2nd from the W end is beneath a gablet, with impost band. The shallow N transept has a 5-light window and angle buttresses. Beyond it is a further bay with 3-light window. Set back against the E return wall of the nave is a polygonal porch with ribbed door in a moulded surround and lintel, and cusped lights in the side facets. The N side of the chancel has a single cusped light, and a rose window to the E wall is above a hipped-roof projection with canted mullioned bay windows.
The S side of the main chapel has 3-light windows similar to the N, while the S transept window is only glazed in the tracery lights. There is a short link from the transept to the hall and Sunday school on the S side of the chapel. The hall W elevation has angle buttresses, doorways R and L with ribbed doors under pointed arches with glazed quatrefoils to the tympana. Above each doorway are 3 stepped lights. In the centre is a projecting polygonal bay with 2-light windows, parapet with moulded cornice and red sandstone coping. Above it are shallow buttresses framing triple cusped and transomed windows lighting the gallery, with small window above. The S wall has a cusped lancet at the W end, then 5 cusped lancets grouped together further R. The 1½ storey Sunday school projects on the SE side of the hall. Its W elevation has a pointed doorway to the L with ribbed door under a shouldered lintel and glazed cusped light in the tympanum. To its R are 3 pairs of cusped lights and 2 gabled 3-light roof dormers with timber-framed gables. The faceted S wall has 3-light windows with cusped lights while the E side has two similar 2-light windows and 3 roof dormers similar to the W side. The E side of the hall has an added hipped lean-to below triple cusped lights. The S side of the chancel has a hipped outshut housing vestry and additional school rooms.