Understanding Load Bearing LVL Beams
Laminated veneer lumber beams are made from thin wood layers bonded together. They are often used above openings, under floors, and below roof loads. This calculator gives a planning estimate for a simply supported beam. It checks bending, shear, bearing, and deflection with the values you enter.
Why Careful Sizing Matters
A beam can look strong and still fail a service limit. Bending stress protects the fibers from overstress. Shear stress checks splitting near supports. Bearing stress checks crushing where the beam sits on a post or wall. Deflection checks comfort, finishes, and visible sag. All four checks matter because real buildings need strength and stiffness.
Formula Used
The tool converts area loads into line loads with tributary width. Uniform load equals total floor or roof load multiplied by tributary width. Maximum moment for a simple span is wL² divided by 8. A center point load adds PL divided by 4. Maximum shear is wL divided by 2 plus half of the point load. Bending stress equals moment divided by section modulus. Shear stress equals 1.5 times shear divided by area. Deflection uses standard elastic beam equations for uniform load and center point load.
How to Use This Calculator
Enter actual span between supports, not total board length. Choose the total beam width by multiplying ply width and ply count. Enter the manufacturer rated bending value, modulus of elasticity, and shear value. Use conservative loads when the exact design is unknown. A ratio below one suggests the entered member passes that specific check. A ratio above one suggests resizing, shortening span, reducing load, or getting engineering help.
Practical Construction Notes
LVL beams depend on proper bearing, fastening, lateral restraint, and moisture protection. Multiple plies must be connected as required by the supplier. Holes and notches can reduce capacity. Support posts and foundations must also carry the reaction forces. Include beam self weight when members are deep, long, or built from several plies. Review drawings for hidden point loads from girders, posts, stair openings, or roof valleys. This page is useful for early estimating, comparison, and learning. It is not a stamped design. Local codes, permits, and manufacturer span tables should guide final construction decisions.