The mansion at Caerau comprises a late seventeenth century house joined to a block of about 1730 with extensive later additions.
The original house is a two storey building with cellar and attics. It has stone rubble walls under a slate gabled roof hipped to the south-east. It faces south-west, where an off centre doorway opens onto a passage with a stair at the rear and rooms to either side. The stair is original as is the panelling in one of the ground floor rooms. On the south-east side of the house is a walled court with late seventeenth century gatepiers at the entrance. This aligns with the avenue (below) and the piers may have been moved as they do not correspond with the contemporary house.

The eighteenth century block faces north-west across the garden and was joined to the rear of the house by a connecting wing. It presents a polite asymmetrical six bay facade under a steeply pitched slate gabled roof with a massive ridge top chimney stack and slighter end stacks. The roof pitch is shallower at the rear where it covers a parallel range with upper storey dormers. The main range has a kitchen and pantry and the upper floor has three rooms, two opening off a back passage. The kitchen retained a remarkable array of original fittings in 1937, when one of the upper rooms had an original landscape painting on a panel above the fireplace.

Various service wings were added to the rear (south-east) of the house, encroaching on the walled court. There was a large garden area to the north-west and the house was approached by a long avenue (see NPRN 86524). North-east of the house is a late seventeenth century stable building (NPRN 31057). A four seat privy to the south-east (NPRN 31056) had fittings similar to those of the eighteenth century block.

Sources: RCAHM Anglesey Inventory (1937), 76
NMR Site File
CADW Listed Buildings Database (5381)

John Wiles, RCAHMW, 18 July 2007