Formula Used
The calculator treats the header as a simply supported rectangular beam. Uniform load is based on area loads and tributary width. Optional line load and center point load are then added.
Uniform line load: w = dead psf × tributary width + live psf × tributary width + extra plf + beam self weight.
Maximum moment: M = wL² / 8 + PL / 4.
End reaction and shear: R = V = wL / 2 + P / 2.
Section properties: S = bd² / 6. I = bd³ / 12. A = bd.
Bending ratio: demand moment ÷ adjusted bending capacity. Adjusted capacity equals Fb × duration factor × S.
Shear ratio: shear demand ÷ shear capacity. Shear capacity is estimated as Fv × A / 1.5.
Deflection: uniform load deflection equals 5wL⁴ / 384EI. Center point load deflection equals PL³ / 48EI.
Bearing: bearing pressure equals end reaction divided by beam width and bearing length.
How to Use This Calculator
Enter the clear span between supports. Add the tributary width carried by the header. Enter dead load, live load, and any extra line load. Add a center point load when a concentrated load sits near midspan.
Choose the number of plies, ply thickness, and actual member depth. Then enter design values from the LVL supplier. Use the deflection limits required for your project. Press calculate. Review the status, controlling check, ratios, reaction, bearing pressure, and estimated maximum span.
LVL Span Header Planning Guide
Overview
An LVL header carries floor, roof, or wall loads across an opening. This calculator gives a structured estimate for that task. It is made for early planning. It is not a permit design. Always confirm final sizes with local code tables or a licensed professional.
What the tool checks
The tool compares your applied line load with several beam limits. It checks bending strength. It checks shear strength. It checks live load deflection. It also checks total load deflection. Reaction values are shown for both supports. Bearing pressure is estimated when bearing length is entered. These results help you see which condition controls the header.
Why inputs matter
Header capacity depends on span, depth, width, material grade, load type, and bearing. A deeper member usually helps deflection and bending. Extra plies increase width and section capacity. Higher loads reduce allowable span. Short bearing areas can create crushing concerns. These relationships are simple, but they matter during framing choices.
Using the answer
Read the status first. A passing result means the selected member meets the entered assumptions. A failing result means one or more checks exceeded the limit. Review the controlling ratio. Then adjust depth, plies, span, or load. The calculator also provides an estimated maximum span. Treat that span as a guide, not as final approval.
Practical cautions
Loads must include all supported materials. Roof snow, attic storage, floor live load, wall weight, and finish weight may apply. Point loads from girders or posts need separate engineering. Holes, notches, moisture, fire rating, and connectors can also change performance. Manufacturers publish specific design values. Use those values when available.
Documentation
Use the example table to compare common entries. Export the result when you need a record. The CSV file is useful for spreadsheets. The simple PDF gives a printable summary. Keep copies with drawings, notes, and assumptions. Good records make reviews faster. They also reduce field mistakes.
Good habits
Measure the clear opening carefully. Use the real supported width. Separate dead load from live load when possible. Check whether the header supports one level or several levels. Confirm end bearing before ordering material. Small input changes can create large design changes. Review assumptions whenever the framing plan changes during construction.
FAQs
What is an LVL header?
An LVL header is an engineered wood beam placed over an opening. It transfers loads around doors, windows, and similar gaps.
Can this replace an engineer?
No. This calculator supports early planning only. Final sizing should follow local code, manufacturer tables, and professional review.
Why does depth change the result so much?
Beam depth strongly affects section modulus and moment of inertia. More depth usually improves bending capacity and reduces deflection.
What is tributary width?
Tributary width is the supported floor, roof, or wall width that delivers load to the header. It converts area load into line load.
What does the highest ratio mean?
The highest ratio shows the controlling check. A value under one passes the entered assumption. A value above one needs review.
Why include bearing length?
Bearing length helps estimate compression pressure at each support. Short bearing can control even when bending and deflection pass.
Can I enter a point load?
Yes. Use the center point load field for a concentrated load near midspan. Off-center loads need separate analysis.
What values should I use for Fb, Fv, and E?
Use design values from the LVL manufacturer. Different grades and products can have different strength and stiffness ratings.