Upper Ericstane, 56 Williaw Street, Helensburgh

Upper Ericstane is a mid-19th century villa, with later additions and alterations carried out by Duncan McNaughtan in 1878 and 1901. It comprises a two-storey, three-bay gabled main block, accompanied by a lower, two-storey block to the north rear. The south elevation is rendered, while the north elevation is harled, with cream sandstone ashlar dressings. The windows are mullioned with chamfered arrises and quoin strips.

The north elevation, facing Montrose Street and the main entrance, features three symmetrical windows on both the ground and first floors. The central ground floor window is narrower than the flanking windows. The ground floor also has decorative iron window guards, and a small bipartite window with multi-pane glazing sits to the outer right. At the first floor, the central window is flanked by semi-circular oriel windows. A fine doorcase leads to an enclosed stair and a side entrance on the west. The door is half-glazed with leaded panes, and the arrises have a stop-chamfered roll-moulding with scrolled skewputts. A low screen wall extends to the right. The enclosed stair has a half-timbered base and timber transomed, round-headed windows with leaded panes above, covered by a lean-to roof. A doorway on the south side has an ashlar balustrade with a pier topped by a ball finial and a half-glazed door with leaded panes. A single-storey wing is attached to the outer left, representing a recent modernization of an older service building.

The south garden elevation has two recessed bays to the left. A doorway is situated to the right, featuring a fanlit, two-leaf, glazed door. A tripartite window is set within a slightly advanced squared bay to the left, and a basket-arched French window is in a slightly advanced bay to the right at first floor. An ogee-headed window is set in an advanced gabled bay, breaking the eaves to the left, and is decorated with a bargeboard. An iron balcony is positioned at the first floor, supported by three cast iron columns. A taller, gabled bay with full-height canted windows is situated to the outer right. The ground floor of this bay is corniced, and it has a piended slate roof.

The west side elevation is gabled, with three bays. A narrow window is centrally placed on both ground and first floors. Blinded windows are to the outer right, while the enclosed stair is to the left. A narrow transomed window with leaded pane glazing is located to the right, with a corresponding window above it at the first floor. A lower, gabled bay extends to the outer left, featuring a first-floor window. The east elevation is gabled with a window to the right at first floor.

The windows are a mixture of plate glass and four-pane sash and case windows, with decorative glazing to the French window and curved glass to the oriels (incorporating fixed multi-pane sections above). The roof is covered with grey slate, and there are ashlar corniced stacks and original cans. Some original rainwater goods remain. The interior was not inspected.

A low ashlar coped rubble screen wall with an ashlar balustrade runs along Montrose Street, with a taller, semi-circular coped rubble boundary wall to the right.