Glulam Beam Sizing Calculator

About the Glulam Beam Sizing Calculator

Glued laminated timber (glulam) is an engineered wood product made by bonding layers (laminations) of dimensional lumber. Glulam combines the beauty of natural wood with engineered-grade strength and is available in sizes and lengths far exceeding solid sawn lumber. It's the go-to product for exposed beams, long-span ridge beams, and heavy-load applications.

This glulam sizing calculator helps you select the right beam width and depth for a given span and load. It uses typical 24F-V4 DF/DF glulam properties (Fb = 2,400 psi, E = 1,800,000 psi) and checks both bending stress and L/360 live-load deflection.

Glulam is manufactured in standard widths (3.125″, 3.5″, 5.125″, 5.5″, 6.75″) and depths in 1.5″ increments (since each lamination is 1.5″ thick). This gives a wide range of available sizes to optimize for your specific requirements.

When This Page Helps

Glulam is ideal for exposed beams and long spans where appearance matters. This calculator helps you quickly find the minimum depth and width to carry your load across the desired span.

How to Use the Inputs

1. Enter the beam span in feet.
2. Enter the total uniform load on the beam (plf).
3. Select the glulam width.
4. Read the minimum depth required for bending and deflection.
5. Choose a standard depth (in 1.5″ increments) at or above the minimum.

Example Calculation

Tips & Best Practices

• Glulam depths come in 1.5″ increments: 9″, 10.5″, 12″, 13.5″, 15″, 16.5″, 18″, 19.5″, 21″, etc.
• For exposed applications, specify "architectural appearance" grade—it costs more but has a smooth, attractive finish.
• Glulam beams can be cambered (curved upward) in the factory to offset dead-load deflection.
• The 24F designation means the extreme fiber stress in bending is 2,400 psi—it's the most common residential grade.
• V4 means the bottom laminations are tension-rated—always install glulam with the "TOP" stamp facing up.
• Protect glulam from prolonged moisture exposure—seal the end grain and apply a UV-resistant finish for exterior use.

Common Glulam Grades

24F-V4 DF/DF is the most common residential grade: Fb = 2,400 psi, E = 1,800,000 psi, Fv = 265 psi. 24F-V8 SP/SP is a Southern Pine alternative with slightly different properties. 20F-V7 is a lower grade sometimes used for purlins and secondary members.

Glulam Connections

Concealed connections are popular for exposed glulam: knife plates, concealed beam hangers (Simpson CCQ), and through-bolted connections. For heavy loads, steel plates and through-bolts provide the highest capacity. Always use the connector manufacturer's published values.

Cost Comparison

Glulam typically costs 30–60% more than LVL per lineal foot at equivalent capacity. The premium buys appearance-grade finish, wider standard widths, and longer available lengths. For concealed beams in floor systems, LVL is usually more cost-effective.

Frequently Asked Questions

• What is the difference between glulam and LVL?

  Glulam is made from stacked layers of dimensional lumber (horizontal laminations), giving it a natural wood appearance. LVL is made from thin rotary-peeled veneers (like plywood but in beam form). LVL is narrower (1.75″ per ply) and typically used in concealed applications.

• What width of glulam should I use?

  3.5″ fits inside a 2×4 wall; 5.125″ fits inside a 2×6 wall. For exposed beams, 5.125″ or 6.75″ are common. The wider the beam, the shallower it can be for the same load, but wider beams cost more.

• Can glulam be used outdoors?

  Yes, with proper treatment and finishing. Specify "industrial appearance with preservative treatment" for outdoor structural applications. Seal the end grain and apply a UV-protective finish. Re-coat every 2–3 years.

• What is the "TOP" stamp on glulam?

  Glulam is not symmetrical—the bottom laminations are higher-quality tension-rated wood. The TOP stamp indicates which face must be installed facing up. Installing it upside down significantly reduces its capacity.

• How far can a glulam span?

  Residential glulam beams commonly span 20–32 ft. For commercial and heavy-timber construction, glulam can span 60–100+ ft in arched or truss configurations. The maximum span depends on depth, width, grade, and loading.

• How do I support the ends of a glulam beam?

  Glulam requires adequate bearing area at supports. A minimum 3.5″ bearing length is typical for light loads; heavy loads may need 5″+ or a bearing plate to distribute the reaction. Use Simpson concealed-beam connectors (?"CCQ, HUC) for clean installations.