3-1/2 in x 16-1/2 in Glulam Beam — 20 ft is a glued-laminated structural wood beam listed by Johnston at approximately 3-1/2 in × 16-1/2 in and 20 ft long.

Glulam selection is engineering-sensitive. Match the exact beam dimensions, stress class/combination, species/layup, camber and appearance classification shown on the beam stamp or project documents. Do not use a generic family image or catalog title to infer allowable loads; final sizing, connections and bearing requirements must follow the engineered design.

Documents & Resources

• Doug Ashy Buying Guide: Doug Ashy Engineered Lumber Buying Guide
• Industry Standard: APA — The Engineered Wood Association: panel and engineered wood standards