The Edwardian Gothic main wing of Wesley dates from 1917 and was designed by the winner of a competition Byera Hadley (1872–1937), an English-born architect who had emigrated to Australia in 1887. Construction of the design was expected to cost £20,000. The brown face brick and sandstone building originally consisted of the central wing, dining room, chapel and Master's residence. It has a steep slate roof and is topped with a copper flèche. The interiors are detailed in a neo-Gothic style with polished timber staircases and wainscotting, leadlight windows and quatrefoil plaster ceilings. The chapel was paid for by benefactor Frederick Cull.
