Austin joined Corderoy in 1982 and has been a partner since 1998, most recently running the firm's London office.
A non-practising lawyer, Austin has worked on projects such as a Sikh temple in Southall, west London, and civil engineering projects for the London Docklands Development Corporation.
Partner John Marsden said Austin had been picked because of her age and experience. He said: "It's for continuity and for the future of the firm. It makes a lot of sense." Austin said she wanted to improve communication between all parties, to build on Corderoy's existing client and consultant relationships, and to bring added value to projects the QS was involved with.
Corderoy, founded in 1780, has 250 staff and has 26 offices in the UK, Europe, the Middle East and the Far East.