Henry John Treadwell was born in Lambeth, Surrey [now London], England in 1862. He was articled to Franklin & Andrews of Ludgate Hill, London, and was then assistant to the Giles Gough & Trollope in London.
Treadwell established his own independent architectural practice in London in 1884 and from 1890 to 1910 was in partnership with Leonard Martin (1869-1936) as Treadwell & Martin.
Treadwell & Martin were responsible for leaving a "trail of remarkable little buildings across London's West End" [Edwardian Architecture: A Biographical Dictionary' by A. Stuart Gray (London: Gerald Duckworth & Co. Ltd., 1985 p.353),
Photographs of the the entrance hall of 'Pyports' in Cobham, Surrey, a dining room fireplace at Cobham, and the drawing room and dining room fireplaces at 'The Lych Gate House', Cobham, designed by Treadwell & Martin, are illustrated in 'The Studio Yearbook of Decorative Art' 1907 (pp.74, 113, 114, 115). The Treadwell & Martin partnership was dissolved following the death of Treadwell in 1910.
Treadwell's address was given as 2 Waterloo Place. Pall Mall, London in 1904. He died in London in on 24 October 1910.
Works by Treadwell & Martin included the rebuilding and later addition of St. John's School, Leatherhead, Surrey (1890s); St. Mary's Hospital 'later Children's Hospital], Carshalton, Surrey (1890s); Cottage Hospital, Cobham, Surrey (1890s); Scott's Restaurant, 18-19 Coventry Street, London (1892-94); Rising Sun public house, Tottenham Court Road, London (1897); St. John's Hospital in Lisle Street, London (1897-1904); Old Shades public house, Whitehall, Westminster, London (1898); Furness office building, 60 St. James's Street, London (c.1900); 7 Hanover Street, London (c.1900); Panton House, Haymarket, London (c.1900); office building, 74, New Bond Street, London (c.1900); office building, Whitehall House, Whitehall, Westminster, London (1904); Sandroyd School, Cobham, Surrey (1905-06); 78 Wigmore Street, London (1906); office building, 106 Jermyn Street, St. James, London; 78-81 Fetter Street, Holborn, London (c.1906); office buildings, 55 and 20 Conduit Street, Mayfair, London (1907); office buildings, 23 Woodstock Street and 7 Dering Street, London (1907). Other buildings by the partnership included Joyce Green Hospital in Dartford, Kent; the Southern Hospital in Carshalton, Surrey; several public houses and breweries, including the Black Swan in Carter Lane, London, and the Old Dover Castle in Westminster Bridge Road, London; hotels, including Shelley's Hotel in Albermarle Street, London; churches, including the Presbyterian Church in West Norwood, the Holy Trinity Mission Church at Tulse Hill, London, and St. John's Church at Herne Hill in Surrey.
Directory of British Architects 1834-1914. Compiled by Antonia Brodie, et al. Volume 2: L-Z. London; New York: British Architectural Library, Royal Institute of British Architects/Continuum, 2001
Gray, A. Stuart. Edwardian architecture: a biographical dictionary. London: Gerald Duckworth & Co., Ltd., 1985
‘Obituary’. The Builder vol. 99, 5 November 1910 p. 559
Roberts, H. V. Molesworth. ‘Some early modernists’. The Builder 29 January 1943 p. 106