Evaluation of Check Size in Glued Laminated Timber Beams

Seasoning checks (the cracks that develop in wood as it loses moisture) are a common occurrence in glued laminated timber (glulam) beams. While often cosmetic, checks can sometimes affect a beam's structural integrity, particularly its horizontal shear capacity.

This publication is designed for: engineers, architects, designers, builders, contractors

This publication provides a comprehensive, practical framework for evaluating the size and significance of checks in glulam bending members. It offers guidance on how to measure checks, determine their location relative to the shear-critical zone and calculate allowable check sizes.

Key sections include:

• Introduction to seasoning checks in glulam

• Distinguishing seasoning checks from delamination

• Evaluating check size in glulam bending members

• The shear-critical zone

• Allowable check size (inside and outside the shear-critical zone)

• Evaluating check size with reduction in shear capacity

• Example calculations

Published by APA — The Engineered Wood Association.