Glulam
Summary
Glulam is a structural member of lumber layers bonded with moisture-resistant adhesives so the grain runs parallel to the length, with lumber at 8 to 14 percent moisture content. Member size is limited by transport and handling rather than tree size, and curved arches span up to 94 m, so glulam suits long spans and exposed structure.
Cols
Terminology
- Lamination: an individual layer of lumber
- Finger joint: end joint between boards
- Appearance grade: surface finish level; faces sanded or planed, knots filled
- AITC: American Institute of Timber Construction (formed 1952)
- ANSI A190.1: glulam manufacturing standard
History and demand
Invention
- 1901 Swiss patent and 1906 German patent for curved sections: Otto Hetzer
- 1942: water-resistant phenol-resorcinol adhesive allowed exterior use
First uses in construction
- 1860s: principles believed to date to Southampton, England
- 1934: first United States glulam project, a school and gym in Peshtigo, Wisconsin; Max Hanisch brought the technology to the United States
- 1963: first United States manufacturing standard
Sourcing
- 2024: Austria produced about 1.43 million m3 of glulam and Germany a record 1.32 million m3 (Timber-Online)
- United States about 414,000 m3 and Canada about 35,000 m3 in 2020 (Statista)
Composition and production
Manufacturing process
- Lumber dried and graded, end-jointed with finger joints, glued and pressed, then finished
Properties
Mechanical
- Arches span up to 85 m (PostFinance Arena) and 93.967 m (Alumni Coliseum)
Fire behavior
- Flammable, but a char layer protects the interior and helps it retain strength for some time
Standards
Material specifications
- ANSI/APA A190.1: structural glued laminated timber
- ASTM D3737: structural glued laminated timber properties
Uses in buildings
Building elements
- Glulam Beams: beams, columns, and arches
- Timber Bridges: bridge girders and arches
Pros and cons
Pros
- Long spans and curved shapes
- Char layer protects the interior in fire
- Size set by transport, not tree size
Cons
- Flammable
- Needs moisture control (lumber 8 to 14 percent at gluing)
Manufacturing and cost
Main manufacturers and suppliers
Trade association: American Institute of Timber Construction.
Sources
- Wikipedia: Glued laminated timber, https://en.wikipedia.org/wiki/Glued_laminated_timber
- UpCodes: 2024 IBC Chapter 23 wood, https://up.codes/viewer/department-of-defense/ibc-2024/chapter/23/wood
- Wikimedia Commons: Glued laminated timber house.jpg, photo by Дмитрий Кошелев (Public domain), https://commons.wikimedia.org/wiki/File:Glued_laminated_timber_house.jpg
- Timber-Online: production headed towards the 3-million-m3 mark in 2026, https://www.timber-online.net/wood_products/2026/05/glulam-production-stable-at-a-high-level.html
- Statista: US glulam timber production, https://statista.com/statistics/238006/us-glulam-timber-production