4 Union Street

4 Union Street is part of a three-storey industrial terrace located at 1-5 Union Street in Penygloddfa, Newtown. The terrace features two-storey, one-window houses with weaving lofts above. It is constructed from English garden wall bond brick, with Nos 3, 4, and 5 being painted. The gently pitched slate roof is old slate for Nos 1 and 2, while the eaves cornice is saw-toothed. No 1 has a brace plate, and there are lateral chimneys at the rear.

The weaving lofts over Nos 1 and 2 have three-light casements, while the other windows are modern. The first and ground floors of Nos 1, 2, and 5 have cross windows, with others also being modern. The windows feature cambered header arches, shallow reveals, and no sills. There is a cut window flanking the door of No 5. The doorcases are plain with brackets supporting the dripboards, and the doors are modern. Additionally, there is a later continuous lean-to outshut at the rear.