LVL Beam Load Calculator

Calculator Input

Clear Span Feet, center bearing to center bearing.

Tributary Width Feet of supported floor or roof width.

Live Load psf

Dead Load psf

Point Load lb, enter 0 if none.

Point Load Location Feet from left support.

Ply Thickness Actual inches per ply.

Number of Plies Use 1, 2, 3, or project value.

Beam Depth Actual LVL depth in inches.

LVL Density pcf for self weight.

Allowable Bending Fb psi from product data.

Allowable Shear Fv psi from product data.

Modulus of Elasticity E psi

Compression Perpendicular Limit psi for bearing check.

Bearing Length Inches at support.

Load Duration Factor Use 1.00 unless adjusted.

Deflection Limit Use 360 for L/360.

Example Data Table

Span	Beam Size	Tributary Width	Live Load	Dead Load	Point Load	Typical Use
12 ft	2 ply 1.75 x 11.875 in	8 ft	40 psf	15 psf	1000 lb at midspan	Interior floor beam
16 ft	3 ply 1.75 x 14 in	10 ft	30 psf	20 psf	0 lb	Roof girder planning
10 ft	2 ply 1.75 x 9.5 in	6 ft	40 psf	12 psf	750 lb at 4 ft	Short header check

Formula Used

Uniform Line Load

Uniform load equals area load times tributary width, plus beam self weight.

w = (LL + DL) × TW + self weight

Section Properties

The calculator treats the LVL as a rectangular built-up member.

A = b × d

S = b × d² / 6

I = b × d³ / 12

Support Reactions

For a simply supported beam with uniform and point loads:

R left = wL / 2 + P(L - a) / L

R right = wL / 2 + Pa / L

Stress and Deflection Checks

fb = M / S

fv = 1.5V / A

Uniform deflection = 5wL⁴ / 384EI

The script also samples the span for combined point-load deflection.

How to Use This Calculator

Enter the clear beam span in feet.
Add tributary width from supported joists or rafters.
Enter live and dead loads in psf.
Add any point load and its location from the left support.
Enter actual LVL ply thickness, ply count, and depth.
Use product design values from the manufacturer.
Choose the bearing length and deflection limit.
Press calculate and review the governing ratio.
Download CSV or PDF for project records.

LVL Beam Load Planning Guide

Why LVL beams matter

Laminated veneer lumber is common in modern framing. It offers steady strength, long lengths, and predictable stiffness. A calculator helps organize early beam checks before drawings are finalized. It turns floor area loads, roof loads, point loads, and self weight into line loads. Then it estimates bending, shear, deflection, reactions, and bearing demand.

Key design ideas

A simply supported beam carries load to two supports. Uniform load comes from joists, rafters, decking, finishes, and live use. Point load may come from a post, girder, trimmer, or concentrated roof reaction. The span controls moment strongly. Small span changes can change deflection and bending demand a lot. Depth usually helps stiffness more than added width. Wider plies still improve bearing, shear, and bending capacity.

Reading the result

Use the governing ratio first. A ratio under one suggests the selected size passes the entered checks. A ratio over one warns that demand exceeds the chosen limit. Review bending stress, shear stress, deflection, and bearing separately. A member can pass strength and still feel bouncy. It can also pass deflection yet fail bearing at a short support. The reaction values help size posts, footings, hangers, and connectors.

Practical construction notes

Measure span from bearing center to bearing center unless your designer states another rule. Use actual LVL dimensions, not only nominal labels. Enter realistic dead load. Include ceiling, flooring, roofing, sheathing, and mechanical items. Live load should match the intended occupancy. Snow, attic storage, balconies, and tile floors can raise demand. Moisture, drilling, notching, fire rating, and connection details also affect final approval.

Better planning habits

Use conservative inputs when loads are uncertain. Save each run with project notes. Compare several beam depths before choosing plies. A deeper beam often reduces deflection sharply, while extra plies mainly raise strength, bearing, and connection area during planning.

Limits and professional review

This tool is for planning and education. It uses simplified simply supported beam equations. It does not replace local code checks, manufacturer tables, lateral restraint review, vibration review, or engineered drawings. Final LVL selection should be confirmed by a licensed professional or the product manufacturer. Always follow span tables, fastening schedules, hanger requirements, and inspection rules for your project.

FAQs

What is an LVL beam?

An LVL beam is laminated veneer lumber. It is made from bonded wood veneers. Builders use it for headers, girders, and long-span framing where stable strength is needed.

Does this calculator replace engineered design?

No. It is for planning checks only. Final beam selection should follow local code, product tables, connection details, and review by a qualified professional.

What does tributary width mean?

Tributary width is the supported area width feeding load into the beam. For floor joists on both sides, it often equals half the joist span on each side.

Why is deflection important?

Deflection controls movement and service comfort. A beam can pass strength checks but still sag too much for finishes, doors, windows, or floor feel.

What is the governing ratio?

The governing ratio is the highest demand-to-capacity value. A value below one suggests the entered member passes these simplified checks.

Should I include beam self weight?

Yes. This calculator adds self weight from beam area and density. It is usually small, but it improves load accuracy for larger members.

What load duration factor should I use?

Use 1.00 when unsure. Different codes and products may allow adjustments for snow, wind, or short-term loads. Confirm the correct value before construction.

Why can bearing fail first?

Short bearing length concentrates reaction force. Even a strong beam can crush support material or exceed compression limits if the bearing area is too small.