Some parts of the exterior were not seen at resurvey, especially the North and South-west Outer Courtyards, but there is a full description in RCAHMW.
The castle is built of local limestone rubble with Sutton stone and sandstone dressings, which is, on the whole, matched very carefully in its different builds and periods; see, for instance, the south wall of Bradenstoke Hall which incorporates medieval and 1920s walling as well as introduced medieval features. The roofs are largely hidden from the ground behind parapets when viewed from outside the castle; the notable exception is the Bradenstoke Hall, which is roofed with stone slates. The ranges round the Inner Courtyard have Welsh slate roofs, but there will also be much lead on the flat tower roofs etc.
Concentric Outer and Inner Curtain walls, part of the course of the Inner Curtain masked and in part lost amongst later buildings (see History). Medieval Outer Gatehouse and Inner Gatehouse with Mansell Tower. The main apartment ranges, Hall etc. are round the Inner Courtyard. The Outer Courtyard and the Outer Curtain were altered in the early C20 by three major additions, the Lady Anne Tower, the Dining Hall and the Bradenstoke Hall.
The castle is surrounded by a partly filled-in ditch on the north and east and by a precipitous slope on the west. Castellated outer curtain walls with corbel table and loops; built in mainly straight sections with corners of wide angle.
The circuit begins with the Entrance Bridge over the dry ditch. The Bridge is stone and carries a paved roadway flanked by castellated parapet walls. It reaches the Outer Gatehouse, with a portcullis in its double-chamfered central arch, an inset coat of arms below the murder chute with two flanking and widely spaced lancet windows. Castellated parapet with arrow loop in the large central castellation. Taller corbelled lookout on the right return and also on the left return with a smaller and taller turret, the latter without corbels.
The circuit is continuous and is described clockwise from the Bridge. The first break in the faceted wall is the east corner of the Bradenstoke Hall which broke through and then incorporated the medieval wall. The wall of the Hall has four 2-light windows which were brought from the Abbot's Lodging of Bradenstoke Priory, Wiltshire in 1929. They are Decorated windows of the C14 and have cusped lights with a quatrefoil above. There is one at each end and a pair in the centre. Only the heads are medieval as is shown by the SPAB poster put up as a protest on the London Underground at the time of the demolition. The poster shows only three windows so the fourth may be replica, or come from the other side of the building. These windows replaced ones previously inserted into the medieval wall by Sir Thomas Garner, which lit Morgan Williams' Armoury. Above the windows is a continuous corbel table supporting a castellated parapet with arrow-loops and behind is the steeply pitched roof with a crow-stepped gable on the right.
At the west end of the Bradenstoke Hall is a doorway with 4-centred head and, above it, a corbelled oriel with a 1 + 4 + 1 light transom window and stone tile roof. This lights Sir Edward Stradling V's Long Gallery. Above this is a 2-light Decorated style window with cusped head and quatrefoil. To the left are four small windows, one to each floor, which light the stair tower.
Now comes the Lady Anne Tower which was largely rebuilt to three storeys by Sir Thomas Garner for Morgan Williams in 1901-9 and then enlarged and raised by a storey by Randolph Hearst in the late 1920s (it is difficult to recognise exactly what happened but both the stonework and the windows of the top floor do seem to suggest an addition, though the work is very carefully matched). It has Tudor type windows with 4-centre head lights within a square head and dripmould on the ground and first floors, three and 4-light ones. The second floor ones have cusped heads of a more Perpendicular type while the top (Allom) floor has cusped headed lights without dripmoulds, 2 + 2 + 2 facing south and 2 + 2 facing east, both with king mullions. Corbelled and castellated parapet with gargoyles and arrow-loops, taller turret behind. The west face of the tower is broader and has ranges of single and 2-light windows on each floor and a massive corbelled stack.
The curtain continues to the projecting Dining Hall which has a small stair turret beside it. The Dining Hall has two tall storeys over a basement and is canted with 1 + 2 + 1 windows. These are large 2-light mullion-and-transom with quatrefoil heads to the Dining Hall and with sunk spandrel heads to the Library above. The basement storey is battered and has small single light windows. On the north return there is a massive chimney stack for the Dining Hall and behind rises the largely hidden but taller Gibbet Tower.
The curtain continues high on a steep bank to the North Tower, which is square with a strongly projecting top and parapet with murder holes, and then through the service yard with a 1920s doorway through to the North Court, and the final section of the medieval wall being the north gable wall of the Medical Block which has two 2-light windows on the ground floor, two arrow-loops above and a crow-stepped gable with central arrow-loop; all these features are likely to be early C20, although the Medical Block itself was built in the late C16. This building abutts directly onto the Outer Gatehouse.
The Outer Court, once continuous between the Inner and Outer Curtains, is now in three parts due to the interruptions of the C16 Medical Block and Long Gallery and the 1920s Bradenstoke Hall and Dining Hall. The court is presumably on the line of the C12 ditch.
East Court, entered through the Outer Gatehouse stretches from the Medical Block to the Bradenstoke Hall. A clock-wise circuit begins with the inner face of the Outer Gatehouse.
The entrance arch has a double-chamfered 3-centred head with a quatrefoil above; visible change in the stonework between the two features. Slit windows to right lighting stair to Guardroom. This section rises higher to a guard turret. Next and directly abutting the gate tower is the late C16 Brewhouse which has three plain rectangular windows on the ground floor arranged 1 + 2 with a 4-centre arch doorway between. The upper floor has two gables each with a 2-light stone mullioned window. Coped main gables. Stair to the wall-walk. The inner face of the Outer Curtain is plain, wall-walk and castellations with arrow-loops above.
Secondary segmental arch with parapet and inset iron overthrow between the outer wall and the Mansell Tower. The outer wall continues to a break at the corner of the Bradenstoke Hall where steps go down into the gardens. The Hall east gable has a 5-stepped-light window.
The South-east Tower next to it has an early C14 rendered face with lancets and arrow-loops, the castellated parapet is later. Then comes the Inner Gatehouse with adjacent Mansell Tower; the east face of the Inner Gatehouse with a plain 3-centred arch with a sandstone roundel with an indecipherable inscription probably added by Dr. Nicholl-Carne; this is set above the corbel table and between flanking loops with single light window with dripmould over.
Finally comes the early C16 Medical Block. This has two 3-light Tudor windows on the ground floor, with, to the right, a single light one and a 4-centred doorway. Above are three 3-light windows as before.
North Court not seen at resurvey.
South-west Court not seen at resurvey.
Inner Courtyard with buildings of mostly two storeys with attics and of different dates of construction (see History); buildings with stone walls of different heights, but all with castellated parapets above corbel tables with the attic dormers hidden behind the parapets. The circuit of the Inner Courtyard goes clockwise from the entrance gate.
West side of Inner Gatehouse with roundel with Berkerolles arms and an otherwise plain wall rising to a castellated parapet.
West side of Mansell Tower with a possibly C16 terracotta roundel of the Emperor Caligula (Newman says it's a copy of the one at Hampton Court). see also below. This tower is three storeys with a battered base and the base of the walls are now known to incorporate the remains of the C12 Keep, rising through the first floor on the west face. The ground floor has a plain 2-light window, above is a more elaborate Tudor one, then Caligula and above him is a plain flat-headed 2-light window and finally the castellated parapet, the top features are C19. Surviving C12 features include dressed Sutton stone doorways, windows, arch responds etc.
The South-east Block is of early C16 date and abutting onto the Great Hall; windows mostly renewed; 2-light mullioned windows to the ground floor; transomed and mullioned first floor windows, two 2-light and one 4-light and the return with a smaller 3-light one. Above, behind the parapet, there are five idiosyncratic 3-light dormers which must also be by Garner, range of four stone stacks above.
The C15 Great Hall (or Stradling Hall) with the Stradling entrance at its east end. The Stradling entrance or porch has a probably original 4-centred doorway with restored 3-light oriel window over (this was re-instated by Atlantic College in the 1960s); lateral stone benches behind entrance; moulded rear doorway to Great Hall. Early C20 4-light transomed window by Thomas Garner to the hall and, in the west projection, a restored 3-light Perpendicular window. To the west of the Great Hall, a higher corner bay with an early C20 4-centred doorway on the ground floor and 4-light transomed window above.
The West Range is of c1500 to 1525, but now only on this outer face as it was gutted, extended and rebuilt behind in the late 1920s to mid 1930s. Three full height rectangular bay windows, the northern one at least, together with other restoration work here, by G F Bodley (see Buckler drawings and Bodley plans), the windows all have 4-lights and two transoms; rainwater heads of 1901. More dormers as before are hidden behind the parapet. Two terracotta roundels between the bay windows, probably by Giovanni de Maiano, and said to be Marcus Aurelius and Cleopatra. They are part of a set of twelve intended for Cardinal Wolsey at Hampton Court where the others still are. They have certainly been in-situ since 1804 and possibly from the C16. Small door in the north corner with single light windows above and the Gibbet Tower rising behind
The western part of the North Range of c1500 to 1525; restored early C20 with windows that date to design of T Garner; rainwater heads of 1901. Transomed and mullioned windows with dripstones; also single light windows; mostly restored or renewed, two of 3-lights to the ground floor and another above, with two 2-light ones to the left and a shorter 2-light one without transom to the right. In the centre, 3-centre headed doorway with dripmould and roundel with Stradling arms above. More dormers are hidden behind the parapet, but these are of a plain 2-light gabled design and are probably from the 1930s. Two tall stone stacks in the centre.
The North-east Block joins the North Range to the Inner Gatehouse. This block incorporates the so-called Below Priest's Room which is of earlier date; three storeys; two single light windows with dripstones to each floor and a small C19 oriel window also to left hand on first floor; doorway with large buttress to its left hand; C19 bellcote on roof. Stone steps against east gable. The North-east Tower is behind, but this can only be seen from the North Courtyard.