Leaving the Ministry of Health he formed and managed building and land development companies in the Cardiff and London areas. He was one of the founders and for some years the secretary of the Welsh Housing and Development Association; he edited The Welsh Housing Year Book for 1916, 1917, and 1918. (For a list of companies with which he was connected see Who's Who in Wales, 1937). Later he devoted himself to local government affairs, serving on many councils (including the Glamorgan county council) and their various sub-committees; he was also a Privy Council representative on the Court of Governors of the National Library of Wales. In 1948, he was awarded the degree of M.A., honoris causa, by the University of Wales.
His main publications, apart from contributions to newspapers and journals (he was for a time editor of The Welsh Outlook) are: Gwalia's Homes, 1911; Pithead and Factory Baths (with J.A. Lovat-Fraser), 1920; The Housing Problem in Wales1920; History of the Port of Cardiff, 1939; Historic Melingriffith, 1940; The Government of Wales, 1943; Wake up, Wales, a Survey of Home Rule Activities, 1943; Cardiff's Civic Centre, a Historical Guide, 1946.
He m. Alice, dau. of Caleb Thomas, Ystalyfera, and they had one son. Chapell d. 26 Aug. 1949 at Cardiff.
Sir William Llewelyn Davies, M.A., LL.D., F.S.A. (1887-1952), Aberystwyth