Frequently Asked Questions
Can glulam be used in one-hour fire-rated construction?
Structural glued laminated timber (glulam) can be used in fire-rated construction. The National Design Specification®
(NDS®) for Wood Construction includes a procedure for calculating the fire resistance of exposed timber members.
Exposed glulam timbers can be designed for a fire resistance rating of up to two hours.
Glulam can also be encased by protective materials such as gypsum wallboard to increase its fire resistance. The protective
material insulates the glulam, protecting it from the high temperatures of the fire. Recent research at the USDA Forest
Products Laboratory suggests that a single layer of 5/8 in. Type X gypsum wallboard will provide 30 minutes of protection
and two layers will provide 60 minutes of protection.