Drummillig House, 146 Sinclair Street, Helensburgh

Drummillig House, located at 146 Sinclair Street in Helensburgh, is a 2-storey, asymmetrical L-plan Arts and Crafts villa built in 1909 by A N Paterson. The exterior is harled with painted ashlar dressings.

The west elevation features a canted porch set in a re-entrant angle, topped with a bell-cast roof and bracketted swept eaves. It has a segmental-arched doorway with a half-glazed boarded door, and bipartite windows with arched lights on either side. A cill course runs along the base, and the porch is adorned with red tiles and a glazed vestibule door. There is a stepped 4-light Elizabethan stair window in the angle of the returning wing to the right, which has lead-pane glazing with stained glass. To the outer right, a slightly advanced crow stepped gable is present, along with an advanced chimney wall at the center that features a corniced stepped stack at the apex and a window to the left at ground level with a roll-moulded architrave. The wing to the left of the porch has 2 windows at ground level and 3 at the first floor. A lower 2-storey wing to the outer left contains 3 windows at ground level and 2 at the first floor. The return to the north has a gambrel roof, an off-centre right segmental-arched doorway, a tripartite window to the left, and a doorway to the outer right, with a flat-roofed dormer above.

The south elevation features a full-height, flat-roofed canted window to the outer left and a lop-sided gable bay to the right with an apex stack, along with a window at both ground and first floor levels.

The east elevation, facing the garden, includes a canted window to the left with a piended slate roof and a single-storey sun-lounge to the right with plate glass. At the center of the first floor, there are two canted oriels with a mutual piended roof, overhanging swept eaves supported by timber brackets, and bipartite windows on either side.

The north elevation has a deep canted window off-centre to the right and a later 2-storey wing projecting to the north, which is harled with a red tiled roof.

Inside, the villa features original chimneypieces, a coved ceiling in the drawing room, and a walnut stair and gallery leading to the first floor.

The boundary wall and garages enclosing the forecourt consist of rectangular-plan double garages with a gambrel roof, flanked by a harled wall with red brick coping. There are also two semi-circular arched gateways with brick keystones and iron gates that provide access to the forecourt at the entrance front.