Glulam Beam Size Calculator

When it comes to structural design, choosing the right beam size is one of the most important steps for safety, performance, and cost-efficiency. Glued laminated timber—commonly known as glulam—is a popular engineered wood product used for beams, arches, and columns in both residential and commercial projects.

But how do you know which glulam beam size is suitable for your span, load, and deflection requirements? That’s where the Glulam Beam Size Calculator comes in.

This tool simplifies complex structural calculations by providing quick recommendations for beam width, depth, deflection, and load capacity. Whether you’re an engineer, architect, builder, or homeowner planning a project, the calculator helps you make informed decisions before finalizing structural designs.

How to Use the Glulam Beam Size Calculator

Using the tool is straightforward. Here’s a step-by-step guide:

1. Enter Clear Span
   • Input the distance the beam must cover without support.
   • Example: 20 feet.
2. Enter Spacing Between Beams
   • Define the spacing of adjacent beams.
   • Example: 6 feet.
3. Input the Uniform Load
   • Combine live and dead loads (psf).
   • Example: 50 psf.
4. Select Glulam Grade
   • Choose from options such as 24F-1.8E (premium), 24F-1.5E (standard), or 20F-1.7E.
5. Choose Allowable Deflection
   • Options include:
     • L/240 for general floors and roofs
     • L/360 for tighter floors
     • L/180 for roof-only applications
6. Click “Calculate”
   • The calculator will analyze moment, shear, and deflection requirements.
   • Results are displayed with recommended beam size, maximum moment, shear, and warnings (if any).
7. Copy or Share Results
   • Use the built-in copy or share buttons to save or distribute your beam calculations.

Practical Example

Let’s say you’re building a residential structure with the following details:

• Clear Span: 18 ft
• Spacing Between Beams: 6 ft
• Uniform Load: 60 psf (live + dead load)
• Glulam Grade: 24F-1.8E
• Allowable Deflection: L/360

After entering these values, the calculator may recommend:

• Required Depth: 18 in
• Required Width: 5.125 in
• Max Moment: 1450 ft-lb
• Max Shear: 2700 lb
• Deflection: 0.55 in
• Grade Used: 24F-1.8E

This provides a quick reference beam size that you can verify with a structural engineer before ordering materials.

Key Features and Benefits

• Instant Results – No manual formulas or tables needed.
• Accurate Calculations – Based on modulus of elasticity, allowable bending, and shear stress values for glulam grades.
• Customizable Inputs – Adjust span, load, spacing, grade, and deflection for precise recommendations.
• User-Friendly Interface – Simple design that’s easy for both professionals and DIYers.
• Built-In Warnings – Alerts you when deflection or strength limits are exceeded.
• Practical Output – Provides depth, width, moment, shear, and deflection values.
• Copy & Share Options – Save results or share them with colleagues and clients instantly.

Common Use Cases

• Residential Construction – Beam sizing for homes, decks, garages, and roofs.
• Commercial Buildings – Structural checks for larger spans in offices, schools, and halls.
• Preliminary Design – Quickly test options before finalizing with engineering software.
• DIY Projects – Homeowners planning remodels or extensions.
• Educational Use – Teaching structural engineering concepts in classrooms.

Tips for Getting the Most Out of the Calculator

• Always enter realistic loads (including both live and dead loads).
• Use standard spacing values where possible to match construction practices.
• Select the appropriate grade depending on whether you need premium or standard performance.
• Treat the tool as a preliminary check—final approval must come from a licensed structural engineer.
• Re-run calculations with different deflection limits if comfort or vibration performance is a concern.

Frequently Asked Questions (FAQ)

1. What is a glulam beam?

A glulam beam is an engineered wood product made by bonding layers of lumber with durable adhesives for superior strength.

2. Why use a glulam beam calculator?

It helps determine the correct size of beam for a given span, load, and deflection limit without manual calculations.

3. Is this calculator a substitute for a structural engineer?

No. It’s a preliminary tool. Always confirm results with a licensed structural engineer.

4. What inputs are required for the calculator?

You need span length, spacing between beams, uniform load, glulam grade, and deflection limit.

5. What is allowable deflection?

It’s the maximum amount a beam can bend under load without affecting safety or performance.

6. Which glulam grades are supported?

Currently, the calculator includes 24F-1.8E, 24F-1.5E, and 20F-1.7E.

7. How accurate are the results?

The results are based on standard engineering formulas and material properties but should be verified by professionals.

8. Can this be used for steel or concrete beams?

No. It is designed specifically for glulam timber beams.

9. What does “Max Moment” mean?

It represents the maximum bending moment the beam must resist, expressed in foot-pounds.

10. What does “Max Shear” mean?

It’s the maximum shear force at the beam’s supports, measured in pounds.

11. What happens if no suitable beam size is found?

The calculator will warn you to consult an engineer for custom sizing.

12. Does the tool consider lateral bracing?

No. It assumes proper installation and bracing are provided.

13. Can I use this tool for cantilever beams?

No, the calculator is designed for simply supported spans.

14. Is the tool mobile-friendly?

Yes, it works on desktops, tablets, and smartphones.

15. Can results be shared?

Yes, you can copy results to your clipboard or share them directly.

16. Does it include snow or wind loads?

It only considers uniform loads (live + dead). Snow or wind should be factored into the load input.

17. What units does it use?

Span and spacing are in feet, loads in psf, and results in inches and pounds.

18. How are beam sizes selected?

It checks standard widths and depths to find the smallest size meeting moment, shear, and deflection requirements.

19. Can DIY homeowners use this?

Yes, but results must still be reviewed by professionals before construction.

20. Is the calculator free?

Yes, it’s a free online tool for quick glulam beam sizing.

Conclusion

The Glulam Beam Size Calculator is a powerful, easy-to-use tool that simplifies structural design decisions. By entering a few key values, you can instantly see recommended beam sizes along with load and deflection details.

While it’s not a substitute for professional engineering review, it serves as a valuable starting point for builders, designers, and homeowners. Using this tool can save time, reduce guesswork, and improve the accuracy of your construction planning.