Built-up beams (multiple 2x boards nailed together) carry loads across openings. These are rough maximum spans for a beam supporting one floor level — the real span depends heavily on the load width it carries.
| Built-up beam | Approx. max span |
|---|---|
| (2) 2×8 | about 6 ft |
| (2) 2×10 | about 7 ft |
| (2) 2×12 | about 8 ft |
| (3) 2×10 | about 9 ft |
| (3) 2×12 | about 10 ft |
Load width drives span. A beam carrying a wide tributary area spans far less than these. For anything structural, size the beam with an engineer or official span table.
Estimates for planning only — confirm load-bearing beams with a professional.
FAQ
Can I use a beam span table for any species of lumber? No, span tables are specific to a species and grade of lumber (or engineered lumber product) because bending strength and stiffness vary significantly between species, so always confirm the table matches the actual material being used.
See the Joist Span Chart and the Header Span Chart.
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