Olrig, 10 Hillhead, Bonnyrigg

Olrig is an early 20th-century, two-story house built in an asymmetrical L-plan Arts and Crafts style. The house is harled (roughcast) with decorative cream sandstone ashlar dressings. A continuous cill course runs beneath the ground-floor windows, and an eaves course defines the roofline. Window and corner details feature long and short surrounds, and quoins accentuate the corners. A rectangular, gabled garage, harled in appearance, is attached to the east side of the main house.

The main, northeast-facing elevation has a roll-moulded architraved doorway, incorporating a plain frieze and cornice, which extends over a flanking window at ground level. The door itself is timber-panelled with a small-pane fanlight above. A bipartite window is located to the right of the entrance at ground level, with a piended dormer window above. A three-light bay window with a parapet sits in the left-hand gabled bay at ground level, with a single window above it on the first floor.

The southwest-facing rear elevation is irregular, comprising six bays arranged in a grouped 4-2 pattern, with a gabled block at the rear of the long arm of the "L" and a two-bay block set back to the right (short arm). The four-bay block features a window at ground level to the right of the centre, another to the right, one to the left, and a non-aligned window above it on the first floor. A further window is at ground level in the outermost left bay. The two-bay block to the right has a small-pane glazed door set to the left of the centre at ground level, with a tall, shouldered wallhead stack above. A narrow window is set near the internal angle to the left, with a box dormer window above.

The northwest-facing side elevation is irregular, with two bays. A window is located at ground level in the bay to the left of the centre, with a non-aligned window featuring a semi-circular pediment above. A three-light bowed bay sits at ground level in the outer left bay, with a box dormer abutting a second-floor window above it. A tall, shouldered wallhead stack stands above a blank wall in the centre.

The southeast-facing side elevation (long arm of the "L") is irregular and four bays wide. A bipartite window is at ground level to the right of the centre, with a box dormer above. A part-glazed, timber-panelled door with a rectangular fanlight is set in the outer right bay at ground level. A window is positioned to the left of a curved, crenellated half-height wall at ground level, with a bipartite window behind it on the first floor. A final window completes the ground floor to the far left.

The majority of the windows are timber sash and case with twelve panes. The roof is covered in grey slate, with a red clay ridge and ball finials. Slate is used on the main piended dormer, while felt covers the flat-roofed dormers. The stacks are harled and coped with ashlar, and the coped skews are also ashlar. Cast-iron rainwater goods are fitted.

Inside, architraved timber panelled doors and skirting boards are present. The dining room has a dentilled cornice, while the sitting room features a dentilled and bead and reel cornice alongside a dentilled and shouldered fire surround. A similar stripped fire surround is found in the main hall.

The property's boundary includes stop-chamfered sandstone ashlar gate piers with cornices and capping. The boundary walls are constructed of sandstone rubble with shaped rubble and a curved, stugged ashlar cope.