Cantref Water Filtration Plant

This is a water filtration plant, built in 1926. It is constructed from massive, roughly faced grey limestone blocks with carefully worked edges. The building has slate roofs which project significantly beyond the eaves, and metal spired ventilators rise from the ridge. The main two-story range has a projecting entrance gable in the centre of the east front. The windows are mostly fixed, with 16 panes each, and feature carefully worked ashlar lintels and sills; the lintels are stop-chamfered. A raised plinth and eaves band run along the façade, with the bands extending over raised piers. The wings have prominent outer corner piers, each featuring five bays with a triple 16-pane window above a blocked lunette. The lunettes are constructed with stone voussoirs and have carefully worked sills; the inner piers are pierced by a loading door above a blocked window.

The central projection has a broad, pedimental gable, with a roughly faced band extending across from the eaves. It features a small roundel and plain bargeboards. Three bays form the projection, with the outer bays recessed and containing 16-pane windows on both floors. The central bay is narrower, with a window above a particularly elaborate doorcase constructed from smooth brown sandstone. The lintel above the doorcase is inscribed “Cardiff Corporation Waterworks Cantref Roughing Filter MCMXXVI” above double-panelled doors. Flanking this bay are single bays, each with a 16-pane sash window on both floors. All windows in the central projection have been replaced with uPVC.

The south end has a broad gable with a small roundel light, surrounded by radiating voussoirs, a stone band below the gable, and a broad recessed centre with triple 16-pane windows over a blind lunette. The side bays each contain a single 16-pane window at the upper level. The north end is treated as a tower with broad outer piers and a parapet, with taller piers framing the upper section. The east side of the tower has a triple window above two blocked windows, while the west side has a similar three-light window on the first floor.

The rear west side features five-bay wings framing a central projection that has a flat roof supporting a large iron water tank. The left wing has five bays of triple windows to the upper floor, without lunettes below. The central projection has raised piers at the angles and a heavy, roughly faced top cornice. The north side has two windows above a lunette, and the west side is of three bays with a lunette to the lower floor of the outer bays, with a centrally placed arched doorway within a high plinth. A modern concrete link has been added above the doorway, connecting the filtration plant to a modern building to the west. The right wing is similar in design to the left, however the first three bays are obscured by a flat-roofted, single-story range.