A large and sprawling red-brick Victorian mansion, irregular in plan and with irregular elevations in a mixture of historical styles, resulting from several phases of enlargement by successive generations of the Rolls family between c.1830 and c.1900. A courtyard open to the W is formed by large domestic S and E ranges (the former incorporating the original shooting-lodge) and a secondary service courtyard (stables, coach-houses, etc.) on the N side; and projecting from the NE corner is a diagonal library wing.
Built of red brick with Bath stone dressings, slate roofs and clusters of Tudoresque brick chimneys.
The original building being engulfed by later additions to its N, E and W sides, only its S elevation is exposed. This is 2 and 2½ storeys and 3 unequal bays, the middle one projected, 2½-storeyed and gabled, and the third narrow and 2-storeyed with a gable breaking the eaves, and reduced in both dimensions above the ground floor. The former, which is enriched with brick pilasters, stone bands and gable copings with kneelers, has a shallow rectangular bay window of 4 tall round-headed lights at ground floor, a 1st-floor panel containing another window of 4 round-headed lights, and a round-headed 1-light window in the gable with a neo-Norman style architrave; the latter has a transomed 3-light window on each floor. The first bay has a cross-window at ground floor and a wooden 2-light oriel above, with Perp.-style tracery.
The earliest additions (by Wyatt, c.1837-41) are a neo-Norman style 3-storey tower to the left (W) end and a longer 3-bay range at the right-hand (E) end. The former has pilasters terminating in ball finials and a machicolated parapet; a round-headed doorway at ground floor, coupled round-headed windows at 1st floor and 3 round-headed windows at 2nd floor: most of these features with elaborate neo-Norman enrichments. Its broader W return side has narrow turret-like outer bays clasping a large projected bay window at ground floor and set-back upper floors with a gable crouching between the turrets. All these features are encrusted with neo-Norman detailing; and the ground floor bay window has the initials of J.E.W.Rolls in raised brickwork. A neo-Norman arcaded parapet to this window is continued at right-angles across the top of a flat-roofed projection from the side of the great hall to the left (built 1858). The c.1840 addition to the right of the original house is of 3 unequal bays in a slightly less eccentrically eclectic style except for the third, which is treated as featured corner tower: from a large and strongly battered stone plinth, rising in a single attenuated stage to above eaves level, this has one unusually tall round-headed lancet window, a smaller one rising into a gablet, and a corbelled pyramidal roof carrying a narrower clock-house stage with a steep 2-stage ogival cap finished with a weathervane finial. The E return side, 3-storeyed from a lower ground-level (containing service rooms at basement level, and small parlours, a staircase and bedrooms on the upper floors) is relatively simple, having 3 round-headed windows on each of the first 2 levels, 6 small ones to the top floor (grouped 1:2:2:1), and a steeply-gabled dormer breaking the centre of the eaves.
The last component of the restlessly elaborate S elevation is a conservatory added at the left (W) end in 1885, a structure - by comparison with the rest - of serene simplicity: a 6-bay aracade of large chamfered Tudor arches with a single buttress at the W corner and a plain stone parapet. Its W end wall has 4 pinnacled buttresses, very large transomed windows (bricked up in 1924) and a clerestory of small cusped lights. The buttresses and clerestory continue on the otherwise unwindowed N side (to the courtyard) where there is a Tudor-style doorway in the 5th bay.
The E elevation of the E wing is dominated by Henry Pope's 1880s addition, which is tripartite: a very large projected gable with a 3-storey bay window (mullioned at basement level, mullioned and transomed on the 2 main floors); a lower and narrower 3-storey bay treated as a tower feature, with a pair of segmental arches at basement level, a square transomed 4-light window at 1st floor, an oblong transomed 4-light window at 2nd floor, and a pierced parapet with flaming-urn finials to the corners; and a much lower 2-storey service range treated as if it were a free-standing house in its own right, distinguished mainly by a broad projected bay which rises above eaves level and has a low arched 3-light window at basement level, a large transomed window above, and pinnacled kneelers to the gable coping. (Linked to its SE corner at an angle of 45° is Aston Webb's library wing: see below.)
The courtyard elevations are less easy to read. Although mostly erected in J.A.Rolls's phase of addition in 1870-72, they are more expressive of a patron's unpredictable requirements than of an architect's coherent scheme. Only the style - Tudor - is consistent. Of the S range the main elements from right to left (W to E) are: the great hall; a 2-storey porch which - despite being sited at almost the extreme W end of the whole complex - was the main entrance; a 1-storey linking corridor; and a square 3-storey tower. The great hall, of 3 bays with buttresses and tall transomed windows, though large in itself, is visually dominated by the disproportionately large porch. This has angle buttresses, a carved Tudor-style doorway flanked by 1-light windows, a band carved with the Rolls family motto "Celeritas et Veritas" to the front and "Open House Open Heart" on the right-hand side, a canted oriel above the doorway, and a stepped gable containing a panelled shield. Two bays of single-storey corridor, with buttresses and 2-light windows, link the left side of the porch with the tower in the corner. This has the appearance of a stair-tower but is not, since its ground floor is the 3rd bay of the corridor; above this, each of its 2 exposed sides has a 2-light window at 1st floor and a 3-light window at 2nd floor, and it is topped by a pierced parapet with ball finials to the corners.
The courtyard side of the E wing begins with a relatively narrow 2½-storey element wedged against the NE corner of the tower, and continues with a longer 1½-storey service range (to the N end of which the stable courtyard on the N side of the courtyard is linked). The former (built to house a large billiard room at ground floor) of one structural but 3 architectural bays in a symmetrical composition, has a very large rectangular bay window at ground floor with a transomed 5-light window and a pierced parapet; a central attic gable with kneelers and finials breaking through a pierced parapet; and tall transomed windows. The service range, of 2 wide structural bays separated by a chimney stack, has a projected ground floor dominated by a transomed window matching that of the former billiard room; 3 gabled half-dormers with 2-light mullioned windows; a multi-flue lateral chimney stack interrupting the roof, and a large pryamid-roofed lantern (or ventilator) on the ridge of each half.
By contrast with the foregoing, the N side of the courtyard is both functionally and architecturally coherent, being the entrance range of the stable court. Offset to the right in an otherwise 1-storey range (three 2-light windows to the left, 1 to the right) is a 1½-storey, 3-bay, symmetrical gatehouse which has a large Tudor-arched coach-passage in the centre, a sundial above this, a shallow 3-light window either side, a pair of gabled ½-dormers breaking through a pierced parapet with a carved shield in a central upstand, clustered gable chimneys and a large central lantern with diamond lattice glazing and a swept pyramidal cap with lucarnes and a weathervane finial. The W elevation of the W range, a symmetrical 5-window composition with gabled outer bays defined by buttresses and a gabled ½-dormer in the centre, all these gables with ball finials, has 2-light windows in all parts except those at ground floor of the outer bays which are 3-light. The N elevation of the N range, which has simple segmental-headed 1-light windows with brick surrounds (grouped 3:3:1) has a Tudor-arched coach doorway opposed to that in the S range, with a full height gable over it containing a window like the others, and at the W end is a larger gable containing a segmental-headed loading door. On the E side of the stable court, built in the angle with the end of the service wing, is a large square 2½-storey block under a 2-span roof at right-angles.
The library wing added by Aston Webb in 1896, attached diagonally to the NE corner of the E wing of the main house, consists first of a narrow corridor link but principally of a massively-proportioned single-storey, single-cell library block; both raised over an undercroft. In the front elevation (to the garden) 3 bays of wide segmental undercroft arches (1 to the corridor, 2 to the library) separated by buttresses, form a visual link between the two elements, but above that level they differ greatly, the library being twice the height of the corridor. The corridor has a parapet, beneath which are small 2-light mullioned windows and a central 3-light oriel. The library is of 3 bays, the first 2 having tall 3-stage transomed windows, and the 3rd filled by a projected bay which has a battered brick plinth at basement level and an enormous multi-light mullion-and-transom window (deliberately reminiscent of the oriel or compass windows of medieval great halls). A string-course decorated with carved panels crosses the heads of all 3 windows, and above that is a coped brick parapet raised into shallow gablets over the windows. Behind the one over the bay window is a tall louvred ventilator with a domed cap. The gable end of the library, framed by sturdy full-height buttresses, has a central chimney enriched with carving on 2 levels, flanked by undercroft arches like the others, and transomed 3-light windows to the library itself. At the rear a wide projection houses a central slightly extruded chimney stack flanked by inglenook windows on 3 levels.