Cullis–Hill began working as a professional architect after the Second World War. In a contract position with the
New South Wales Housing Commission, she designed houses as part of Sydney's postwar reconstruction boom. In total, she designed more than 30 houses and around 50 residential alterations. She also designed church and school buildings: these included additions to Gib Gate School in Mittagong (1954–1973) and St James' Anglican Church in Turramurra (1957–1975) as well as the original plans for Wahroonga Nursery School (1954–1955) and the Turramurra Nursery School (1961). Her design for the Wahroonga Nursery School was shortlisted for the
Australian Institute of Architects'
Sulman Award in 1956. Cullis-Hill retired in 1981 and died in 2001. ==Legacy==