Exterior
The college is designed, because of the sloping ground, to stand on three levels. It is in C19 Tudor style in sneck-coursed local limestone ashlar with slate roofs. Gables, where they occur, are coped and chimneys are square. Those of the main south range have diagonally set shafts of Tudor form.
The original entrance elevation to the west consists of a four-storey tower and a contemporary range to its right; the similar range to left is the late C19 addition. The tower contains a Tudor-arched doorway with moulding surmounted by the Recording Angel. Taller Tudor-arched windows to left and right. Above this is a two-storey oriel, canted sided, with mullion and transom windows; a string course at the mid height of the oriel continues the eaves line of the roof each side. The top storey has two windows and the tower is crowned by a parapet above a cornice.
Both the original range to the right and the later range to the left are of two storeys, with attic dormers, five windows to left, four to right. The later work has been designed to bring the original elevation close to symmetry. Mullion and transom windows to the upper storey with traceried heads; the lower windows are clusters of four single lights. The dormer windows have steel casements. To the right is the flank of the original library (now Capel y coed).
The south elevation climbs the hill from left to right. At left is the gable end of the original library at the lowest ground level. Then a four-window range of two storeys and attic, and a six-window range of three storeys and attic, both based at the middle ground level. Gables and dormers alternate in the attic. The main windows are all small, pointed and paired, with recent double-glazing.
Chapel to east at the upper ground level, with round apse. Slate roof with crested tiles. Two light traceried windows. Single opening bellcote at west with bell.
The main quadrangle is on two levels separated by a retaining wall; it is mostly at the middle ground level, with a small formal garden around a lawn. The east range overlooking this quadrangle has mullion windows above and mullion and transom windows below, the latter with iron casements quarry glazed. The refectory range to the north side has high level two-light windows, also in iron and quarry glazed, and modern rooflights.
The additions of 1873 comprise a north west wing, defining a new entrance courtyard at the north. The east side of this wing now includes the main entrance, at middle ground level. Large spreading flight of entrance stairs. Tudor arched entrance with oak screen, containing door to left, tracery above. Five gables, the central one over the door slightly advanced. The upper storey is jettied on segmental arches and plain columns forming an arcade. The range opposite (on the east side of the entrance courtyard) is a service building, with large archway incorporating a pseudo-portcullis. Roof ventilators each end. Storage range, post 1871 and recently rebuilt, to north. The refectory north elevation facing this courtyard has Tudor headed mullion and transom windows with iron quarry lights and buttresses between; small dormers to attic.