What Is a Roof Ridge Beam Load Calculator?
A structural ridge beam (as opposed to a simple non-structural ridge board) carries real vertical load, because the rafters bear directly on it instead of leaning against each other and pushing outward on the walls. This calculator estimates the uniform load along that beam and the reaction force at each support, using the standard tributary-width method engineers use for preliminary sizing.
Use it to get a quick, order-of-magnitude estimate before involving a structural engineer — not as a substitute for a stamped structural calculation.
How to Read Your Results
Total Load on Ridge Beam
The full vertical load the beam must carry over its entire length, combining dead load (roofing, sheathing, framing) and live/snow load across the tributary width.
Uniform Load
The load per linear foot of beam (pounds per linear foot, plf) — the number a beam span table or engineer's calculation typically starts from.
Tributary Width
The width of roof "caught" by the ridge beam. Because rafters lean on the ridge from both roof planes, the tributary width equals the full rafter span (half the span from each side).
Reaction at Each End Support
Assuming a simply supported beam (posts or walls at both ends only, no intermediate support), each end carries half of the total load.
Real-World Example
A roof with 15 psf dead load, 30 psf snow load, a 14-foot rafter span on each side, and a 24-foot-long ridge beam:
| Value | Result |
|---|---|
| Tributary width | 14 ft |
| Uniform load | 630 lb/ft |
| Total load | 15,120 lb |
| Reaction at each end | 7,560 lb |
That roughly 7,560-pound end reaction is what a post, header or wall below each end of the ridge beam needs to be engineered to carry.
Tips for Ridge Beam Design
- This is a preliminary estimate only. Final beam species, size and grade must come from an engineered span table or a licensed engineer.
- Point loads from valley or hip rafters landing on the ridge are not included here and can significantly increase local load.
- Intermediate posts change the reaction distribution — this calculator assumes only two end supports.
- Snow load varies widely by region and roof shape — always use your local code's ground/roof snow load, not a generic number.
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Last updated: August 2026 · Reviewed by: Simple Calculator Tools Editorial Team