THE HISTORY OF GLUE-LAMINATED TIMBER

1866 The first glulam elements are used to build the Assembly Room at King Edward VI College in Southampton, England (Leonard, 2008).

1901 The first glue-laminated timber assembly is patented in Switzerland by Otto Karl Freidrich Hetzer (Lehman, 2018).

1906 Hetzer recieved a patent for curved glue-laminated timber (Lehman, 2018).

1934 Unit Structures, Inc., the first US-based glulam manufacturer is founded in Peshtigo, WA (Lehman, 2018).

Unit Structures, Inc. recieves it’s first two commisions - one for the Peshtigo Gym and the second for a storage building for the Forest Products Laboratory.

Late 1930s Several more glulam manufacturing companies are established. Projects include schools, gyms, stadiums, churchs, factories, and aircraft hangers.

resin glues are fully waterproof and resist fungal growth, which made exterior applications possible (Saleh Pascha, 2014). These glues continued to be improved to the point where the adhesive bond in the glued joints became stronger than the bond between the wood fibers themselves (Saleh Pascha, 2014). Modern synthetic resins are inexpensive, easy to apply, and have become so finely tuned that their setting times can be adjusted to facilitate a speedy manufacturing process (Saleh Pascha, 2014).

Modern mass timber adhesives have also come a long way in minimizing the impact of VOCs. Since 2018, the EPA has regulated formaldehyde emissions in laminated wood products. Strict limits have been placed on the formaldehyde off-gassing during production and after curing in the final product that have significantly lowered the environmental and health life cycle impacts of glues (US EPA, 2023). In general, polyurethane and phenolic adhesives are preferred over ureaformaldehyde and melamine adhesives.

Given that modern mass timber buildings use adhesives that are far superior in strength and water resistance to those used historically, it’s reasonable to expect that the lifespan of a mass timber building completed today can far exceed those of historic structures that remain in use today.