18 Alexandra Place, Sion Mills, Co Tyrone, BT82 9HR, *** See General Comments***

18 Alexandra Place is a mid-terrace one-and-a-half-storey house built around 1880 as worker's housing for the Herdman's Mill in Sion Mills. It is located on the west side of Melmount Road, forming part of a terrace of eleven houses, and is ninth from the left in the row.

The house is rectangular on plan with a two-storey flat-roofed extension added to the west around 1985. The roof is pitched natural slate with terracotta ridge tiles over deep overhanging eaves, decorated with timber bargeboards. A roughcast chimney with concrete coping and replacement clay pots rises from the roof. The walls are painted roughcast over a smooth banded plinth.

Windows are timber casements in smooth rendered reveals with painted masonry sills. The principal elevation faces east and contains a square-headed opening at right with a replacement vertically-sheeted timber door and transom, a single window at left, and a central gabled dormer to the attic. Cast-iron half-round gutters and round downpipes drain the roof.

The south gable is abutted by the neighbouring house (HB10/07/009Q), while the north gable is abutted by HB10/07/009S. The west elevation is abutted by the extension, which contains two windows at first floor. At ground floor, a single-storey lean-to extension abuts this elevation, containing a replacement door at centre flanked by windows on each side.

The house is directly accessed from the street at the east. A roughcast boundary wall with concrete coping encloses a rear yard, accessed through a vertically-sheeted timber gate.

The ground floor return has been substantially remodelled and extended to include first-floor accommodation around 1985. The house first appears on the third edition Ordnance Survey map of 1905 as part of the terrace along Alexandra Place. Valuation Revisions of 1879 record that houses were "in Progress" at that date, with numbers 3–20 valued at £2 10s each and listed as "house, office and yard" with various occupiers.

Sion Mills was established as a company-owned model village by Herdman & Co., a flax spinning mill run by the Herdman family. By 1853, the works employed over 500 workers. Single and two-storey dwellings were constructed to house mill workers, following a planned layout comparable to Sir Titus Salt's work at Saltair. Until the 1960s, when the village was privatised due to a slump in the linen industry, the Herdmans maintained comprehensive village services including a shop, dispensary, doctor's house and surgery, fire service, and a trained workforce for maintenance and repairs. Workers paid rent and gas charges fortnightly, and contributed a small weekly sum—one penny in the early days, sixpence in the 1940s—towards healthcare, with the Mill employing a doctor and nurse.

Due to alterations and extensions affecting this house and the adjoining terrace, the small-scale houses have lost considerable original architectural character both individually and as a group. Their general massing and historic interest mean they still contribute to the Sion Mills Conservation Area.