According to Theodore H. M. Prudon in “Preservation of Modern Architecture,”
“One lesser-known invention is glue-laminated timer, which made it possible to manufacture wood structural members of smaller sizes, larger spans, and greater consistencies than standard wood beams. Section of wood, generally 1 or 2 inches thick, are laminated together with the grain parallel longitudinally. While the material may be employed as beams or columns, its most dramatic use has been in the form of arches, trusses, and shells allowing for clear spans well beyond what would be possible with regular wood members. The material remains in use today for many structural applications where the use of reinforced concrete or steel members is not desired, inappropriate or cumbersome.
[...] The idea of using glue rather than clamps is generally attributed to Karl Friedrich Otto Hetzer (1846-1911) from Weimar, Germany, others greatly contributed to developments in this technology. Hetzer took out a series of patents between 1891 and 1910 dealing with different aspects of wood construction. In 1906 he received a patent for a curved member composed of two or more laminations permanently glued together and resistant to moisture: the clear-span timber arch was born. Patents were taken out in various European countries, and licenses were granted. Buildings with laminated members referred to as the Hetzer construction method spread from Germany to Scandinavia, the Netherlands and the Dutch colonies, Italy, and finally, the US. [...] The technology as invented by Hetzer was introduced in this country by Max Hanisch Sr. (1882-1950), who emigrated in 1923 and settled in Racine, Wisconsin.”
- Prudon,Theodore H. M., Preservation of Modern Architecture. Hoboken: John Wiley & Sons, Inc., 2008.