Exterior
The Mission Hall has a front in Arts-and-Crafts style, of brick with stone dressings, lintel and sill bands, with rubble stone side and rear walls, under a slate roof, which is hipped to the front. The front is divided into 3 bays by pilasters. In the centre bay is a pair of recessed doorways behind original iron gates and beneath keyed segmental heads with projecting hood moulds. Each has half-glazed panel doors under a small-pane segmental overlight. There is another front entrance in a lower link on the L side between Mission Hall and Lesser Hall, which has a flat roof concealed behind a coped gable with original rainwater goods. The link has a similar doorway and iron gates to the central bays of the hall. In the outer bays of the Mission Hall are 2 small-pane windows with moulded transoms. Above the sill band are foundation stones laid by several individuals, including John Pugh and Seth Joshua. At the upper level the central bay is filled with a wide 6-light window, which is continued by 3 lights in the outer bays to create a continuous glazed strip, helping to give the front a distinct secular character. There is a deep dentilled eaves.
The R-hand side wall is partly rendered, after a former attached building was taken down. The 6-window side walls have, under brick segmental heads, on the R-hand side, 2 tiers of T-shape wood-framed windows with coloured leaded lights, while on the L side the less-visible windows above the link have been replaced by plastic units. Walls curve round to the rear, with further segmental-headed windows, to a projection at the rear housing the organ and minister’s room beneath it.
The earlier chapel, known as the Lesser Hall, is to the L. It is set back from the street behind dwarf stone walls (original railings have been removed), and is built of rubble-stone walls under a slate roof. The gable-end front is cement rendered and is in a very simple classical style, with round-headed openings. There are 2 doorways in the centre, with panel doors and overlights, between which is a foundation stone, recording Davies as architect and Thomas & Cox as the builders. The doorways are flanked by wood-framed fixed windows and there are similar windows at the upper level lighting the former gallery, flanking triple round-headed windows in the centre. In the rear wall are 2 round-headed windows with wooden Y-tracery.