A fashionable architect in the inter-war years, Williams-Ellis's other works include buildings at Stowe in Buckinghamshire; groups of cottages at Cornwell, Oxfordshire; Tattenhall in Cheshire; and Cushendun, County Antrim, Northern Ireland. Williams-Ellis is also known for his design (in the 1930s) of the former summit building on Snowdon, which — after unsympathetic alteration in the 1960s and a long-term lack of maintenance — was described by Prince Charles as the highest slum in Wales.