Thirlstane House

Thirlstane House is an early 19th century, two-storey, three-bay rectangular-plan house with later additions. It features lower single-bay wings connected by a recent single-storey addition to L-plan cartsheds and outbuildings. The exterior is harled with raised sandstone dressings.

On the northwest (entrance) elevation, the house has a three-bay layout with gabled wings. A central gabled porch with timber bargeboards and finials projects forward, with a doorway on the right return leading to a panelled door. There is a window to the northwest, while the left return is blank. Each wing has single windows on both floors. The lower wings on either side have single windows at the ground floor, and first-floor windows that break the eaves in pedimented dormerheads. To the right, there is a lower four-bay modern wing with a doorway in the left bay and windows at the ground floor, as well as breaking eaves at the first floor in pedimented dormers located in the outer right bay and the penultimate bay to the left. There is also a window at ground level in the penultimate bay to the right. Single-storey outbuildings are attached to the outer right.

The southeast (rear) elevation features seven bays with irregular-sized windows in each bay.

The southwest elevation includes a single-storey range of outbuildings that were formerly cartsheds. There are three keystoned basket-arched cart arches on the outer right, which are now blocked, with one featuring a window and another a door. A garage with two-leaf doors is located on the outer left, along with two louvred ventilators topped with pyramidal caps.

The northeast elevation is a blank gable. The house has sash and case windows with various glazing patterns, a grey slate roof, and shouldered polygonal stacks.