A stretcher and English garden wall bond structure with a gabled roof and full length ridge ventilator. The roof has been re-clad with Fibro-cement sheeting.
The powerhouse is associated with the Katanning Roller Flour Mill. Piesse established the power plant in 1902 to power his mill. In 1904, a private Act of Parliament allowed Piesse to generate and supply power and lighting to the town. Katanning was one of the firsts towns in Western Australia to have electricity. In the late 1920s, the electric light and power plant was upgraded, and the new generator supplied the town until 1961, when the SEC (now Western Power) purchased the power plant and electrical distribution system for £85,125, converting it to AC power the following year. 1980 - Sign writer Ray Ford bought and continued his business from the building. 1990 - Jeremy George used the back rooms for an upholstery business.