Bolt: Wednesday's Word Of The Week

One galvanized bolt (silver) & one galvanized + powder coated bolt (black)

There are many pieces of standard hardware used in glulam and timber construction. One that is certainly not unique to wood construction is the bolt. ¾"ø hex head bolts are the most common fastener used in Unalam projects. Dimensionally, they are the same as bolts used in steel construction, although usually much longer. Other bolts sizes, from ½"ø to 1"ø are fairly common.

A307 is the standard material grade for bolts in glulam construction. These are mild steel bolts as opposed to high strength A325 or A490 bolts used in steel construction. The high strength bolts are not necessary in wood design, because bolt deformation and wood strength are the limiting design factors rather than bolt fracture. 

Arbor with galvanized bolts installed

Unalam supplies hot dip galvanized (rather than unfinished) bolts on all projects. We believe this is best for the longevity of the structures, and avoids rust stains which could occur from bolts left out during construction.

*Wednesday's Word Of The Week is a feature on Unalam's Wood Times Blog. Each Wednesday our structural engineer, Rik Vandermeulen, will discuss a new term associated with glulam manufacturing. He will do this until we run out of words. If there is a timber or glulam term that you have heard of and want to know more about, let us know in the comments.