The building has an unusual construction history. Originally a stuccoed wooden Palladian-Baroque structure designed by Robert Charles Wetherall, it was incrementally transformed into stone Decorated Gothic, initially to an 1848 design by William Thomas, with Thomas's chancel and the first two bays of his nave being added to Wetherall's existing wooden church, the resulting hybrid being dubbed "the humpback church." The stone gothic nave was completed to a further design by Henry Langley (the architect of some 70 Ontario churches) in 1876, the original wooden portion having been demolished in 1872 to clear room for it and, "inter alia", the chancel extended in 1924–25.