Pyro Building P6 (Carillion Building 45) at Rhydymwyn Valley Site

A very large building of reinforced concrete frame construction with infill of red brickwork laid in English bond. Similar to Pyro buildings P4 and P5, but reversed by 180 degrees. Seven bays to long (east and west) elevations; on lower level of E elevation each bay formerly had 2 openings (ie 14 in all) now blocked. The central section of 5 bays has segmental concrete vault over each bay. At each end a bay with flat roof. Six bays externally to short elevations Square concrete tower to S over second bay from E. Much alteration and blocking of original openings.

The interior is articulated by reinforced concrete posts; some circular openings to roof. Overhead rails for lifting gear. Building is divided longitudinally into 2 areas; to W an area of 2 wide bays, and to E an area of 3 more narrow bays; this area has been subdivided to make laboratory/ office areas. Marks in floor from bases of gaseous diffusion machinery. At S end of W area, small single-storey division probably for switch room. At upper level against N and S walls, steam air heating ducts.