The “Owner’s Guide to Understanding Checks in Glued Laminated Timber” is a document that provides detailed information on the phenomenon of checking in glued laminated timber (glulam).
Glulam is an engineered wood product used in various construction applications, including floor beams, ridge beams, window and door headers, columns, and trusses. Because glulam members are often visible in open designs, seasoning characteristics, typically called “checking,” can be more noticeable and raise concerns with the building owner.
Checking is the separation of continuous wood fibers and is a consequence of the seasoning process of wood. The outer portion of the timber member loses moisture at a much different rate than the inner portion, causing the wood to check. Checking increases the differential moisture content between fibers and thus increases the propensity for checking in the timber. You can find more details in the guide below.