[1] He developed an interest in architecture at an early age, encouraged by his parents who bought him a subscription to Australian Home Beautiful as his eleventh birthday present.
[2] In 1946 he took over the editorship of Smudges, the monthly news sheet of the Architectural Students Society of the RVIA, from Robin Boyd, carrying on the championship of modern design.
He married Sonia Cole in 1955, their first home for a few months being a flat in Regents Court on Toorak Road, before moving to the glass-walled house he designed for his family in Fawkner Street, South Yarra.
He took an active interest in the new discipline of heritage in the 1970s, joining the Buildings Committee of the National Trust of Australia (Victoria), and served as chairman then president of the Council for the Historic Environment (1977–84).
[5] It is not known how many of these were ultimately built, but the service sold hundreds of his plans during his tenure, and examples can be found throughout Melbourne's huge suburban areas developed in the 1950s and 1960s.
As described by architectural academic Prof Philip Goad, "This is typical Clerehan: understated, self-effacing and underestimating his own consummate skill in being able to provide an elegant backdrop to everyday life.
[citation needed] In the late 1960s, his efficiency in house planning led to a commission from Pettit & Sevitt, a Sydney-based project home builder.
Pettit & Sevitt offered a wide range of plans to suit various sites and budgets in Sydney, Melbourne and Canberra, designed by noted architects such as Ken Woolley of Ancher Mortlock Murray & Wooley and Harry Seidler, all with a similar aesthetic of white board or bagged brick walls, flat or cathedral ceilings with exposed beams, and open plan living spaces with generous walls of glass opening onto decks and gardens.
[10][11] In 1969, in association with Ancher Mortlock Murray & Woolley, Clerehan designed the 3136 (a very efficiently planned small flat roofed three bedroom house, named for its 11 square size of 31x36 feet), which won the Project Home Award from the New South Wales chapter of the RAIA in both 1970 and 1971.
[5] In 1972, again with Ancher Mortlock Murray & Woolley, he designed an even smaller house, the 2937 (29 x 37 feet), which received the 1973 NSW Project Home Award.