Table of Contents
What Is Glulam?
Glued laminated timber, also known as glulam or GLT, is a type of engineered wood product made by bonding together several layers of dimensional lumber with high-strength adhesive. Glulam can be used in a number of building applications, including use as supporting members for roofs and floors, structural columns, and arches. The bonding adhesive used to make glulam is usually a type of moisture-resistant resin, such as phenol formaldehyde or melamine formaldehyde. This ensures that glulam beams remain stable even in damp or humid conditions, and many glulam products are rated for exterior or industrial exposure under ANSI A190.1 standards.
Glulam is produced in a wide range of standard sizes and shapes to suit different design requirements, but a big attraction of glulam is that it can also be custom-made for specific projects. Curved or angled glulam members can be created by bending or cutting the individual pieces before they are bonded together. This means that glulam can help realize unique architectural designs, such as dramatic arches or long-span roof beams. Glulam beams can be used for spans of more than 100 feet.
Typical density values for glulam range between 32 and 40 pounds per cubic foot (513–641 kg/m³), depending on the wood species used. The weight values produced by the calculator and shown in the table below derive from a set value of 35 pounds per cubic foot, which is consistent with commonly published APA and manufacturer data.
Wood Types, Dimensions, and Standard Weight of Glulam
Glulam beams in the United States are most commonly manufactured from two species groups: Douglas-fir and Southern Pine. Both species are covered under ANSI A190.1, the national consensus standard for glulam production, and are widely available in standard grades such as 24F Douglas-fir and 24F Southern Pine.
Standard glulam beam dimensions follow a limited set of nominal widths and depths rather than being completely arbitrary. Many stock beams are manufactured in standardized widths of 3-1/8 inches, 3-1/2 inches, 5-1/8 inches, 5-1/2 inches, 6-3/4 inches, 8-3/4 inches, and 10-3/4 inches, with depths ranging upward from 6 inches to 48 inches or more in 1-1/2 inch increments. These dimensions are standardized so that glulam can integrate smoothly with common framing layouts and structural requirements.
The standard design tables published by the APA use a reference density of 35 pounds per cubic foot (pcf) for calculating beam weights. In practice, actual beam weight depends on wood species and moisture content, but engineers and manufacturers commonly use 35 pcf as the baseline density for glulam beams.
Beam Dimensions
The terms “width” and “depth” may be slightly confusing. Here’s a diagram so you know what width and depth refer to.
Example: Glulam beam 3.5″ width × 10″ depth.
Glulam Beam Weight Calculator
This calculator assumes a density for glued laminated timber of 35 pounds per cubic foot (pcf). There are glulam products that vary from this weight value, so you should always check the manufacturer’s technical data sheet for the exact product you intend to use.
This calculator takes decimal inputs.
- 1/8 = 0.125
- 1/4 = 0.25
- 3/8 = 0.375
- 1/2 = 0.50
- 5/8 = 0.625
- 3/4 = 0.75
- 7/8 = 0.875
Glulam Beam
Weight Calculator
Result
Adjusting for Heavier or Lighter Glulam
This calculator uses 35 pounds per cubic foot as the baseline density. If your glulam product is heavier or lighter, you can scale the result with a simple multiplier.
Formula:
Adjusted weight = Calculator result × (Alternate density ÷ 35)
Examples:
- Alternate density is 32 pounds per cubic foot. Multiplier = 32 ÷ 35 = 0.9143, so multiply the calculator result by 0.9143.
- Density 36 pounds per cubic foot: multiplier = 36 ÷ 35 = 1.0286.
- Density 40 pounds per cubic foot: multiplier = 40 ÷ 35 = 1.1429.
About The Glulam Weight Table
The following table provides the approximate weight (dead load, self-weight) for glulam beams used in building construction in the U.S. The table provides the weight per cubic foot as well as the weight per linear foot for various dimensions of glulam members. The values given in the table are meant to provide a general idea of typical weights for glulam beams, and should not be used if precise values are needed for critical engineering calculations.
I also provide weights for dimensions (such as 1/4 inch) that are not the actual dimensions of any real glulam beam. I did this to make it easier to use the table to calculate weights for custom beam dimensions that don’t have published standard weights and are not listed in the tables.
Remember: When precision is necessary, always refer to the specification sheet for the actual product you intend to use, or contact the technical department of the manufacturer.
Table: Glued Laminated Timber (Glulam) Weights
Glulam typically weighs around 35 pounds per cubic foot, or about 3 pounds per board foot. (The trick is to figure out how many cubic feet are in the beam.)
| Weight of Glulam (Glued Laminated Timber) | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 35 Pounds per Cubic Foot (lbs/ft3) | ||||||||||||||
| 2.92 Pounds per Board Foot | ||||||||||||||
|
Table Shows Weight per Linear Foot for Standard Glulam Beam Widths (1 inch is not a standard width) and a Sample of Glulam Beam Depths |
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Glulam is not typically manufactured in widths or depths of less than 3 inches. Weights for dimensions smaller than 3 inches are included to make it easier to calculate weights for custom beam sizes not included in the table. |
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| Width of Beam in Inches |
Depth (Height) of Beam in Inches | |||||||||||||
| ↓ | 1/8 inch | 1/4″ | 3/8″ | 1/2″ | 5/8″ | 3/4″ | 7/8″ | 1″ | 2″ | 3″ | 4″ | 5″ | 10″ | 20″ |
| 1 inch | 0.03 lbs | 0.07 | 0.09 | 0.13 | 0.16 | 0.18 | 0.21 | 0.24 | 0.49 | 0.73 | 0.97 | 1.22 | 2.43 | 4.86 |
| 3-1/8″ | 0.1 lbs | 0.19 | 0.28 | 0.38 | 0.48 | 0.57 | 0.66 | 0.76 | 1.52 | 2.28 | 3.04 | 3.8 | 7.59 | 15.2 |
| 3-1/2″ | 0.11 lbs | 0.21 | 0.32 | 0.43 | 0.53 | 0.64 | 0.75 | 0.86 | 1.7 | 2.56 | 3.4 | 4.26 | 8.51 | 17.01 |
| 5-1/8″ | 0.16 lbs | 0.31 | 0.47 | 0.62 | 0.78 | 0.93 | 1.09 | 1.24 | 2.49 | 3.73 | 4.99 | 6.23 | 12.45 | 24.92 |
| 5-1/2″ | 0.17 lbs | 0.33 | 0.51 | 0.67 | 0.84 | 1 | 1.17 | 1.34 | 2.67 | 4.02 | 5.35 | 6.69 | 13.37 | 26.74 |
| 6-3/4″ | 0.2 lbs | 0.41 | 0.61 | 0.82 | 1.03 | 1.24 | 1.44 | 1.64 | 3.29 | 4.92 | 6.56 | 8.21 | 16.41 | 32.81 |
| 8-3/4″ | 0.26 lbs | 0.53 | 0.8 | 1.06 | 1.33 | 1.59 | 1.86 | 2.13 | 4.26 | 6.38 | 8.51 | 10.64 | 21.27 | 42.53 |
| 10-3/4″ | 0.33 lbs | 0.65 | 0.98 | 1.3 | 1.63 | 1.96 | 2.28 | 2.62 | 5.23 | 7.84 | 10.45 | 13.07 | 26.13 | 52.26 |
Further Information about Glulam
To learn more about glulam, visit the websites of the APA (Engineered Wood Association) and the AITC (American Institute of Timber Construction). They have detailed information about engineered wood applications, beam sizing, design tables, product guides, and more. You may need to create a free account with them in order to access the publications (in PDF) that contain the most detailed technical information.
In particular, for technical data covering the physical properties of glulam beams, including weight per foot and allowable loads, see Glued Laminated Beam Design Tables. (This is a document produced by the APA but made available on the International Code Council website. Use the table of contents on the left side of the screen to view the different sections.)
Weights for plywood, OSB, and other engineered wood panels can be found in my article here.
About the Author
Jack Gray spent 20 years as a principal roof consultant with the Moriarty Corporation, an award-winning building enclosure consultant firm founded in 1967. Mr. Gray has worked in the roofing industry for over 25 years, with training and practical experience in roof installation, roof inspection, roof safety, roof condition assessment, construction estimating, roof design & specification, quality assurance, roof maintenance & repair, and roof asset management. He was awarded the Registered Roof Observer (RRO) professional credential in 2009. He also served as an infantry paratrooper in the 82nd Airborne Division and has a B.A. from Cornell University.