2 x 4's may be later than 42' ?
Glue Lam – History
Resin glues
When glued laminated timber was introduced to the building technology in the early twentieth century,
casein glues, which are waterproof but
have low shear strengths, were widely used. Joints with casein glues had detachment failures due to inherent stresses in the wood.
The invention of cold-curing synthetic resin glues in 1928 ("Kaurit") solved these problems -
resin glues, which are inexpensive and easy to use, are waterproof and enable high adhesive strength. The development of resin glues contributed to the wide use of glued laminated timber construction.
[12]
A significant development in the glulam industry was the introduction of fully
water-resistant phenol-resorcinol adhesive in 1942. This allowed glulam to be used in exposed exterior environments without concern of gluline degradation.
By the early 1950s, there were at least a dozen manufacturers of glued-laminated timber in the United States. In 1952, these manufacturers joined to form the American Institute of Timber Construction (AITC).
The first U.S. manufacturing standard for glulam was published by the Department of Commerce in 1963.
[2]:4 ?
This association sponsored the first national manufacturing standard in 1963, CS 253-63 Structural Glued-laminated Timber (10). AITC has continued to sponsor revisions to the standard. The first was PS 56-73 in 1973 that also became an ANSI standard, A190.1-1973. ANSI A190.1 was revised in 1982 and 1992. The latest version is known as ANSI/AITC A190.1-1992 (2).