Calculator Inputs
Example Data Table
| Example | Span | Beam | Load | Material Values | Use Case |
|---|---|---|---|---|---|
| Floor beam | 12 ft | 2 ply 1.75 x 11.875 in | 55 psf over 6 ft | Fb 2600, E 2000000 | Interior floor support |
| Roof beam | 10 ft | 2 ply 1.75 x 9.5 in | 35 psf over 5 ft | Fb 2600, E 2000000 | Simple roof opening |
| Header check | 8 ft | 3 ply 1.75 x 9.5 in | 45 psf over 4 ft | Fb 2800, E 2000000 | Wall opening planning |
Formula Used
Total uniform load: w = ((dead load + live load) x tributary width) + extra line load + beam self weight.
Beam self weight: self weight = density x beam area in square feet.
Reactions: R left = wL / 2 + P b / L. R right = wL / 2 + P a / L.
Bending stress: fb = M / S. Section modulus S = bd² / 6.
Shear stress: fv = 1.5V / A for a rectangular section.
Deflection: uniform load deflection = 5wL⁴ / 384EI. Point load deflection at load = Pa²b² / 3EIL.
Bearing stress: bearing stress = reaction / bearing area.
How to Use This Calculator
Enter the clear span between supports. Add the tributary width that sends load to the beam. Enter dead load, live load, and any extra line load. Add a point load if a post or concentrated load lands on the beam.
Choose the beam width, depth, and number of plies. Enter design values from your LVL product guide. Press calculate. Review bending, shear, deflection, and bearing ratios. A ratio above 1.000 means the trial beam needs review.
LVL Beam Planning Guide
Basic Purpose
An LVL beam can carry heavy floor, roof, and wall loads. It is made from thin wood veneers. The veneers are bonded under pressure. This gives the member stable strength. It also gives predictable stiffness. Still, every beam must be checked with care.
What This Tool Checks
This calculator helps with early beam sizing. It estimates reactions, bending stress, shear stress, bearing stress, and deflection. It uses common simple span formulas. You can test different depths, widths, plies, loads, and material ratings. The tool then compares demand with selected allowable values.
Input Method
Start with a clear span. Use the distance between supports, not the full board length. Add the tributary width that feeds load to the beam. Enter live load and dead load in pounds per square foot. Add any extra line load when needed. Use point load when a post or concentrated member lands on the beam.
Material Values
LVL products vary by manufacturer. Their published design values can change by series, depth, moisture condition, and duration factor. For that reason, the calculator lets you enter bending, shear, stiffness, and compression ratings. Use values from the current product guide. Do not copy values from another brand without checking.
Deflection and Bearing
Deflection is often the serviceability limit. A beam may be strong enough, but still feel bouncy. The calculator compares total deflection with an L over limit value. Common limits include L over 240, L over 360, and L over 480. Stricter limits reduce bounce and finish cracking.
Support Review
Bearing is also important. High reactions need enough bearing length. If bearing stress is high, increase bearing length, add plies, or choose a wider support. Check posts, studs, hangers, and foundations too.
Final Safety Note
Use the result as a screening guide. It is not a stamped design. Building codes, load combinations, notches, holes, lateral support, fire rules, and connections still matter. Confirm the final beam with a licensed professional before purchase or installation.
Load Path
A final check should include load path. Follow each load to the ground. Floor joists, roof rafters, headers, posts, and footings must align. Small layout changes can move large loads. Keep records of assumptions, product names, and support details. Clear notes make review faster and safer for everyone. Always verify local code requirements before construction starts.
FAQs
1. What is an LVL beam?
An LVL beam is an engineered wood member made from bonded veneers. It is used for headers, girders, floor beams, and roof beams where stable strength is needed.
2. Can this calculator replace an engineer?
No. It is a planning tool. Final sizing should be checked by a licensed professional, especially for structural work, permits, unusual loads, or critical supports.
3. What span should I enter?
Enter the clear span between supports. Do not enter the full purchased length unless the whole length is unsupported.
4. What is tributary width?
Tributary width is the floor, roof, or wall width that sends load to the beam. It helps convert area load into line load.
5. Why does deflection matter?
Deflection controls movement. A beam can be strong enough but still sag too much. Excess movement may crack finishes or feel uncomfortable.
6. What does a ratio above 1 mean?
A ratio above 1 means the calculated demand is higher than the selected limit. Try a larger beam, more plies, better material values, or shorter span.
7. Should I include beam self weight?
Yes. The calculator estimates self weight from density and section area. This gives a more complete total load estimate.
8. Why are manufacturer values important?
LVL design values vary by product line. Always use current values from the selected manufacturer before making a final beam choice.