Structural Beam Replacement Cost Calculator

Dimensional lumber (built-up 2×10 or 2×12) is the most affordable but limited to shorter spans and prone to warping over time. LVL (laminated veneer lumber) is straighter, stronger, and more dimensionally stable — the most common residential beam replacement choice for spans up to 20 feet. Steel I-beams handle heavier loads and longer spans but cost more and require steel column bases.

The complete process: structural engineer assessment and stamped drawings, building permit, install temporary shoring to carry the load, remove the damaged beam, install the new beam with correct bearing length on posts or columns, remove shoring, pass inspection. If the beam is behind finished walls, add drywall removal and replacement at $500-$2,500.

Every structural beam must bear on a properly sized post or column at each end — typically 3.5 inches minimum bearing for wood-to-wood connections. The post must transfer load to a footing of adequate size. A structural engineer calculates all bearing requirements as part of the permit drawings — this is not guesswork.

Minor rot or damage in a single joist or rafter can be sistered (new member added alongside the damaged one) for $200-$600 — much less than full replacement. A main beam with rot through more than 30% of its cross-section, significant insect damage, or fire damage requires full replacement. A structural engineer makes the call.