Beam Sizing Fundamentals
Beams gather joist loads and transfer them to posts and footings. The correct size depends on tributary width, joist span, species, and connection details. Conservative beam sizing improves stiffness and reduces deflection.
Load Path & Layout
- Map joist spans and overhangs to understand tributary widths.
- Place posts to keep beam spans reasonable; add posts rather than over‑spanning.
- Follow connector schedules and fastener requirements.
Material Options
Built‑up PT lumber, engineered LVLs, and steel are typical choices. Follow the manufacturer’s exterior use instructions for engineered products and corrosion‑resistant fasteners.
Plan beams with the Deck Beam Size Calculator (coming soon) and cross‑check with your local span tables.
Resources
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Planning tool only. Results and charts on this site are simplified planning aids based on common assumptions. They are not a substitute for stamped engineering, permits, or inspections. Always confirm with local building officials and product manufacturers.
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