Alltyrodyn, Including Rear Courtyard and Bell Tower

Alltyrodyn is a large country house dating from the late 18th century, built in a style influenced by John Nash. It is constructed of roughcast and colourwashed rubble stone, with hipped slate roofs and two large, axial stacks rendered in a similar finish. Decorative brackets support the flat eaves. The house has three storeys and a symmetrical seven-window front, originally featuring 12-pane sashes on the main floors and nine-pane sashes in the attic, although most have been replaced with late 19th-century plate glass. A broad ground-floor portico with paired Roman Doric outer columns and single half-column responds leads to a central arched first-floor French window. The portico has a cornice with paired modillions and a flat roof, and the small half-glazed double doors are set within a plain architrave. Stone sills are present on the windows. The end elevations have three windows each, illuminating the centre and rear of the building; many of these retain their original glazing bars. The rear elevation features a very large arched stair light with late 19th-century leaded lights, a single window range to the left, and a gabled, lower projection to the right with an arched door and fanlight above a blank arched opening.

A low rear courtyard is constructed of pink-washed roughcast with hipped roofs and lean-to verandahs supported on cast-iron columns. A rear range has had its verandah removed, and the west range was raised a storey in the late 19th century using rubble stone and 12-pane sashes. The rear courtyard's design is strikingly similar to John Nash’s Llanayron. At the rear north-east angle stands a massive ashlar stack belonging to a former bakehouse, and behind the rear range, a two-storey, pyramid-roofed bell-tower with a timber lantern and a wide through arch.

The interior features formal, symmetrical rooms with attractive plasterwork. The entrance hall has double doors with a fanlight leading directly to a stair hall, with doors at each end and a Greek-style cornice of triglyphs and rosettes. Doorcases have a reeded pilaster design. The southwest drawing room retains an Adam-style fireplace, a fine early 19th-century grate, and an original full-length mirror framed to match the doorcases. The northwest room is plainer, but contains a mid-19th-century black Gothic fireplace. A thick spine wall creates a repeating door with a fanlight, visible from both the entrance hall and the stair hall. A moulded cornice runs along the stair hall, leading to a broad, panelled, elliptical arch supported on consoles, which gives access to a broad, open-well staircase with timber stick balusters. From the stair hall, a spine corridor with matching doorcases extends north to the kitchen area and south to a ballroom. The ballroom has a cornice, elliptical arched recesses at each end, and matching doorcases or cupboard recesses. A small, 18th-century style fireplace on the inner wall is not original to the house. A stained glass window on the stair landing features the Stewart arms, and the stair hall has a first-floor modillion cornice with a central rose. A similar elliptical arch is located on the upper landing, which exhibits fine cornice moulding on three sides and arched doorcases leading off. Further spine corridors and an axial passage extend to the arched front centre window. Several good early 19th-century iron fire grates remain in first-floor rooms.

The service court includes a kitchen at the southwest angle, which formerly had a fireplace with a wood surround dated 1827. However, there is some external evidence suggesting that the courtyard may be later than the original house.