James Gillespie Graham, 1813, formerly simple 3 x 6-bay perpendicular gothic nave-and-aisles church, side aisles and nave arcade added by John Biggar, 1891, extensive alterations including 3-bay chancel by Buchanan & Bennett, 1895, raised wallheads and new roof by Reid and Forbes, 1932, hexagonal baptistery to SE by T Harley Haddow & Partners, 1976-77. Polished sandstone ashlar to principal elevation, stugged squared and snecked sandstone with polished ashlar dressings to side and rear elevations.
NE (PRINCIPAL) ELEVATION: symmetrical, 2-tier centre bay, pointed-arched doorway of 4 orders with later 20th century carved timber infill over 2-leaf panelled doors, decorative hoodmould over arch-head rising through string course at base of full-height traceried window rising into gablehead with hoodmoulded arch-head, parapetted skew-copes with cusped arch-heads to blind-arcaded openings and carved cross at apex; 4-tier diagonal buttresses flanking centre bay, breaking eaves as panelled dies with crocketted pinnacles. Traceried windows over substantial base course in bays flanking centre, string course, frieze and mutuled cornice below outer parts of gablehead; single storey aisles flanking principal gable; N aisle comprising pointed-arched recess containing traceried and hoodmoulded window, narrow section recessed at right with panelled timber door in pointed-arch doorway with hoodmould; parapet at eaves, stepped and raised at centre containing small blind lancet; S aisle mirrored image of N aisle, but with no door in recessed section to outer left.
SE ELEVATION: lower portion of elevation obscured by blank wall of S aisle addition; 6-bay side elevation of nave with circular clearstorey window below eaves in each bay; chancel recessed to outer left.
SW GABLE: blank gable with chancel projecting at centre.
NW ELEVATION: single storey 6-bay elevation of N aisle with traceried pointed-arched window in each bay obscuring lower portion of 6-bay N wall of nave, rising behind with circular clearstorey windows in each bay. 4-bay addition to N aisle extending W along Chapel Lane, traceried windows rising into large stone dormerhead breaking eaves in each bay.
CHANCEL: 3-bay sides with traceried windows in each bay, hoodmoulds linked by string course, continuous around canted apse with matching windows to each face.
BAPTISTERY: simple hexagonal form with panelled effect to stonework, 2-leaf timber doors in SE face, short link to S aisle with Dalle de Vere glazing at E and W.
Grey slate roofs; simple pitch to nave, piended W end to chancel, flat roofs to N and S aisles. Cast-iron rainwater goods; ogee-profiled gutters to eaves of nave and chancel, decorative hopperheads (dated 1932) heading square downpipes with decorative brackets, dividing bays of S aisle.
INTERIOR: nave spanning whole width of original church; chancel and aisles running in nave, Gerona fashion. Nave arcade has paired (former) clearstorey windows, cylindrical piers and moulded capitals. Roof supported on painted corbels in form of stylised giant crowned timber angels, carved by Scott Morton, with wings stretched upwards into broad arches; contemporary large brackets for nave and chancel lights. Triple opening in W gable leading to chancel with quatrefoil piers and aisleless chancel. Furnishings include gabled gothic polished stone baldachino by Reginald Fairlie, 1928, central altar by R Rowand Anderson, 1876, stalls and throne adapted by Buchanan & Bennett from earlier work, pulpit by Reid and Forbes, 1932. Stained glass from Munich studio, except 2 windows each of 2 lights by Hardman.
ST ANDREW'S HALL: 1800, with later alterations. 2 and 3-storey 7-bay classical former relief church. Droved ashlar principal elevation with random rubble side and rear elevations with ashlar dressings. Base course, eaves cornice; projecting cills to windows. Principal elevation to SW framed by long and short quoins at corners, oculus to tympanum of advanced and pedimented 3-bay centrepiece, round-arched doorways at ground in each bay, with square stair windows above, and round-arched windows below pediment. Regularly fenestrated outer bays with blind windows, round-arched below eaves. 4-bay side elevations with large segmental-arched windows in 2-storey eastern bays, 3-storey western bay with tall window at 2nd floor and 2 small windows at ground. Symmetrical rear elevation, piend-roof vestry wing obscuring centre and left bays at ground, with segmental-arched window in right bay. Windows at intermediate level in centre bays with round-arched windows above and in outer bays.
12-pane timber sash and case windows, timber mullions to tripartite side windows. Grey slate piended roof with small square wallhead stacks to W corners, and flanking centre bay of E elevation.
TERRACE, STEPS AND RAILINGS: stone-faced terrace with wide flight of steps opposite entrance doors; wrought-iron railings with thistle finials to stanchions; portion of 19th century railings on droved ashlar dwarf wall surviving at E end of Chapel Lane.