Architectural drawings of residential and commercial buildings, job files, incoming and outgoing correspondence, photographs and research material for his book on Walter Burley Griffin. Includes plans by Scorer and Scorer which Birrell obtained when he purchased the firm in 1966. The architectural drawings in this collection include those from his student days, his time with the Commonwealth Department of Works, the Brisbane City Council, the University of Queensland (as University Architect), and his private practices. Drawings for buildings not constructed are also in this collection.

Architectural plans of residential and commercial buildings. Also includes bills of quantities, client files, specification files, job files, miscellaneous papers of A.B. Wilson and R.M. Wilson, and card index of plans by plan numbers, job numbers, and client names. Includes several plans by Alfred Banks.
Also includes rare poster "Victoria Skating Rink, Sandgate". Includes plan of 'University site, St. Lucia. Proposed design', by R.W.J. Hawken, 1929.
Professor Hawken and Alexander Wilson were members of a committee established in 1921 to determine a site for the University of Queensland.

Much of the material in this collection was prepared for a series of residences and plans to be published in the Sunday Mail. Little material can be positively identified. Some of these items have numbers on the reverse which appears to signify that these were plans for actual jobs undertaken by Da Costa. A distinct Spanish influence can be discerned in many of the houses. Many of the plans bear the initials A or B, A meaning wooden construction and B denoting brick construction.