Ashby Bray Tabb was born in Bath, Somerset, England on 14 April 1870. By 1894 he had moved to Birkenhead, Lancashire. In the England and Wales Census of 1901 and 1911 he gave his occupation as decorator. By the 1920s he also worked as an architect. In 1926 he designed 8 Prospect Road, Prenton, Birkenhead. In the 1930s was in partnership with John Knox Vinycomb (1880-1952). In the 1939 England and Wales Register he gave his occupation as architect (retired).
Tabb was the author of a pamphlet entitled Decoration of Passenger Vessels (1934). His address was given as 77 Harlington Road, Toxteth Park, Liverpool in 1901; Woodchurch Road, Prenton, Landican, Cheshire in 1911; Whitethorns, Berry Lane, Chorleywood in 1939. He died in Watford, Hertfordshire on 1 December 1940