5 Cassilus Street, Ayr

5 Cassilus Street in Ayr is a mid-19th century, two-storey, three-bay rectangular-plan house located on a corner site. The exterior features painted render, harl, and rubble, with a base course, cornice, and blocking course. The windows are architraved, with those on the ground floor corniced and cill-blocked.

On the west (entrance) elevation, there are steps leading to a central doorpiece that is corniced, pilastered, and topped with a block pediment. The door is made of timber, and there is a single window aligned above it on the first floor, along with flanking single windows on both floors. To the outer right, there is a single-storey section.

The north (side) elevation has single windows on the left at both the ground and first floors. The east (rear) elevation features off-centre French windows with a fanlight above, and a lower small recessed opening to the right, along with a single-storey section to the outer left.

The property is enclosed by a coped boundary wall. It has plate glass timber sash and case windows, a grey slate roof with a rooflight, stone skews, gablehead stacks, and both circular and polygonal cans. The interior was not seen in 1998.