Question: What is required in specifying preservative-treated glulam beams?

Answer: While glulam does not require preservative treatment in most cases, in certain conditions, for example, where the glulam may be subject to high humidity or moisture content, preservative-treated glulam is required.

To determine the correct preservative treatment of glulam for a specific use, below is a simple list of steps to follow.

I also suggest downloading a copy of APA’s Technical Note: Preservative Treatment of Glued Laminated Timber, Form EWS S580, for more information.

1. Determine the “Use Category” designation that applies to your application. Refer to Table 1 in Preservative Treatment of Glued Laminated Timber for the service conditions/use environment of each Use Category, as defined by the American Wood Preservers' Association (AWPA).

2. Determine the appropriate treatment type for your project.

3. Determine the wood species that will be used in the glulam.

4. Confirm that the specified preservative is recommended for use with the wood species to be used. Refer to Table 3 in Preservative Treatment of Glued Laminated Timber.

5. Note any special requirements, such as pre- or post- treatment preparations.

Please post a comment below if you have any questions or would like additional information or clarification to any of the steps mentioned above.