Are there any tables that compare the load bearing and span characteristics of fir glue laminated beams with solid hardwood beams? I am specifically interested in comparing solid Oregon white oak and bigleaf maple beams to commercially available fir glue laminated beams.
(Sawing and Drying Forum)
From Professor Gene Wengert, forum technical advisor:
Are you in Oregon? If so, you have some excellent Forest Products Extension people there and also a wonderful Forest Products Lab at OSU.
The real issue is, what is the grade of the solid oak and maple beams? With gluelam we can control the quality of the laminations and therefore the overall strength and stiffness within a narrow range. For an equal size, it would not surprise me to see gluelam with spans 50% to 200% more.
In my experience, using gluelams for a 5 foot span in a single story residential structure would be like using a 50 caliber rifle to shoot a squirrel. Building code manuals (are you under the IRC code?) have tables for header sizes, and the strength characteristics for the clear species you mention would seem to exceed those of standard SPF lumber typically considered for code span tables.
"I need a table of comparison for the building inspector."
Sounds like he's being (overly) cautious to me (or covering his butt) - the span and loading are such small values.
Try to get in touch with Scott Levengood - he is a wood extension agent for OSU. He knows what works.