Former Blast Engine Houses at Tondu Ironworks

The former blast engine houses at Tondu Ironworks date from the 18th century and are constructed of roughly dressed ironstone with tooled ashlar and yellow brick dressings, and have a rubble basement. Originally roofed with Welsh slate, they are now roofless. The buildings consist of a larger, rectangular gabled engine house with an added, smaller, setback gabled wing, the second engine house, and have undergone substantial later alterations.

The main frontage features a blind semi-circular arch with a blind oculus at the apex. Below are two floors of round-headed windows with tooled ashlar surrounds, imposts, voussoirs, and keystones, although the glazing has been replaced and is broken. A matching, blocked central former doorway arch of two orders is also present, with tooled quoins. A round-headed red brick arch has been inserted on the left return wall. The right side elevation has two round-arched windows with vermiculated relief keystones, tooled imposts, surrounds, and sills on three storeys, plus a brick window added at first floor level, along with various other openings, some of which are blocked. The rear gable end has two bays and includes similar windows at each level and a wide, blocked semicircular arch with a vermiculated keystone; a door has been inserted to the right.

The left wing frontage has a gable oculus at the apex, and at first floor a large segmental arched window with yellow brick voussoirs and a tooled ashlar surround. A wide segmental arched yellow brick doorway on the ground floor is now partly blocked. Exposed corework on the front left suggests a former attached structure, and there are tooled quoins to the right. The left side elevation has similar segmental arched windows, two on each floor, with larger windows below, and replaced glazing. The rear has an apex oculus, a blocked doorway on the ground floor with a window above (the voussoirs having been replaced by a concrete lintel).

The primary building’s interior is open to the roof and retains trusses of a five-bay roof structure. Large corbels on the end walls previously supported the spring beams for the engine which powered a Boulton and Watt type blast pump. Smaller corbels in the side wall formerly supported a floor; metal track remains to the left, and a steam pipe is visible in the mid-side wall. Furnaces were originally located behind the semi-circular arch in the gable end. A concrete floor was inserted later, likely related to steam turbines installed after iron production ceased. An area of the floor is open to the basement, which reputedly still houses electrical equipment. The rendered foundation structure may be the original foundation for the beam engine. Walls were originally lime rendered, later partly replaced by cement. The second building has two bays and a single roof truss. Blocked round-headed openings precede the main structure, and other blocked openings were created to connect the two buildings; a later brick fireplace has been built across the corner. A later concrete suspended floor is present, but evidence of early engine supports and fittings may exist below; these walls were never rendered, but were limewashed.