The Staal archive consists largely of project files containing design and working drawings, specifications, correspondence and documentation materials. Many of the realized projects are also documented by means of photographs. A model of four designs is also available at the NAI.
The non-project related material consists of sketches and photographs of the various Prix de Rome trips; free work such as (portrait) drawings, designs for posters, book and magazine covers; correspondence with various architects; documents relating to memberships and committee work; articles by Staal explaining his own work, that of others and architecture in general; collected material on architecture and architects. In addition, the archive contains bequeathed documents of his father, the architect J.F. Staal. More archives of J.F. Staal are in the conglomerate archives-Staal (code STAX) in the NAI's collection. These archives are now (2001) accessible only through a placement list. This conglomerate also contains archives of A.J. Kropholler (the father-in-law of J.F Staal) and of Margaret Staal-Kropholler (N.B. wife of J.F. Staal, but not the mother of A. Staal).