4 Sion Terrace, Sion Mills, Co Tyrone, BT82 9HB

A mid-terrace two-storey house built around 1880, fourth from the left in a terrace of seven that fronts the east side of Church Square in Sion Mills. The building is Grade B2 listed.

The house is rectangular on plan with a one-and-a-half-storey gabled return to the west, further abutted by a single-storey gabled extension. The roof is pitched natural slate with terracotta ridge tiles, carried on a corbelled eaves course. It features two rooflights to the east and west pitches. A smooth rendered chimney with clay pots sits on the party wall; a yellow brick corbelled chimney serves the return and its party wall. The main walls are painted roughcast over a smooth banded plinth, whilst the return is smooth rendered.

The principal elevation faces east. It contains, at left, a round-arched-headed opening with a stepped painted brick surround, housing a recessed replacement four-panelled timber entrance door with glazed top lights and transom light. There is a single window at ground floor right, and two windows at first floor. The south gable is abutted by the adjacent property. The west elevation has an exposed section at left with a single window to each floor. The north elevation of the gable contains two windows at first floor and a single window at ground floor; its west and south elevations are blank. The single-storey gabled extension contains two timber casement windows and a replacement timber sheeted door to its north elevation.

Windows throughout are replacement square-headed timber-framed 1/1 sliding sashes in smooth reveals, all with painted masonry sills. The gutters are cast-iron half-round with round downpipes.

The house is directly accessed from the street at the east. A roughcast boundary wall with concrete coping encloses a yard to the rear, accessed through a square-headed vertically-sheeted timber door. A garden lies across a path to the rear, bounded to the east by wire fencing and to other sides by hedging.

The terrace was built as workers' dwellings by Herdman & Co, the flax spinning mill that established Sion Mills as a company-owned model village. The houses were initially single-storey cottages, but second storeys were added to many dwellings at the beginning of the twentieth century, when Captain Ricardo was Director in charge of personnel and welfare. The expansion enabled villagers to take in lodgers during the week as the linen trade boomed from 1903. The terrace first appears on the third edition Ordnance Survey Map of 1905. Annual Valuation Revisions date No. 4 from 1880, No. 5 from 1897, and Nos. 6 and 7 from 1898; Nos. 1–3 appear somewhat earlier. All were originally leased from J&E Herdman.

Despite modern alterations to parts of the terrace—including replacement of some windows and doors—many original features remain intact, notably the yellow brick chimneys and the interior layouts of these simply detailed dwellings. The terrace forms an important architectural group within the model village and benefits from its setting overlooking Church Square. It lies within a conservation area.