Frequently Asked Questions
Treating Glulam Timbers with Waterborne Preservatives
Will pressure-treatment with waterborne chemicals after bonding cause delamination?
Pressure treatment of properly manufactured structural glued laminated timber members will not cause delamination. Delamination
refers to adhesive failure leading to separation of bond lines. Adhesives used in modern glulam products must meet stringent
standards for moisture resistance and durability. Additionally, adhesive bonds in glulam must also pass rigorous daily testing
for strength and durability. Consequently, delamination is very rare in structural glued laminated timber whether it is pressure-treated
after bonding or not. Checks can occur along bond lines due to stress concentrations between laminations and are often mistaken
for delamination. The presence of wood fiber separations or torn wood fibers at the bond line is the key distinguishing characteristic
of checks (AITC Technical Note 11).