In 1895 he moved to
Western Australia, In 1896 he designed the
Great Western Hotel, a three-storey brick, stucco and iron roof hotel, on the corner of James and William Streets,
Northbridge. Cavanagh designed the hotel in the
Federation Filigree architectural style and it was one of the most lavish hotels constructed in Perth during the
Western Australian gold boom. On 11 May 1897 he married Dorothy Le Poer Trench, In 1898 the
Missionary Oblates of Mary Immaculate commissioned Cavanagh to design a new church on the site of a former
Benedictine church in Fremantle. The church is an imposing limestone building in the
Federation Gothic style with decorated Gothic detailing. In 1900 he was joined by his younger brother,
James Charles, who became a partner in the architectural practice,
Cavanagh and Cavanagh. The firm had a long association with the Catholic Church, designing a number of hospitals, schools and churches. In 1924 the
Roman Catholic Archbishop of Perth,
Patrick Clune, commenced an appeal to fund the construction of a larger cathedral, to replace the original 1865 building (which was a simple two storey
Norman Gothic style building), in his own words "building a Cathedral worthy of Almighty God, of the Archdiocese and of the City of Perth". Cavanagh was appointed architect for the project and he produced plans for a completely new limestone
Academic Gothic Cathedral. Due to financial constraints, associated with the onset of the
Great Depression, it was decided to utilise the existing building, which subsequently became the
nave, and add only new
transepts and a sanctuary. The expanded, but incomplete, St Mary's Cathedral opened on 4 May 1930. Cavanagh died at a private hospital in
Subiaco on 29 May 1941, following a two-month illness, and was buried in the Roman Catholic portion of
Karrakatta Cemetery. ==Achievements==