What is the typical spacing for beams?

• A. 8' apart
• B. 20'-30' apart
• C. 4'-8' apart
• D. 12'-20' apart

Answer: (D)

Beams are spaced to balance the load each beam must carry with how far joists or roof members can span between supports. In typical light-frame construction, a spacing of about 12 to 20 feet between beams is common because it keeps the tributary area manageable for standard lumber sizes and helps ensure acceptable bending and deflection without needing oversized members. If beams were placed much closer, you’d end up with more beams and higher cost; if they were spaced much farther apart, the beams would have to be larger to carry the same loads, or the joists would have to span longer than is practical with ordinary lumber. That practical middle ground is why 12'-20' apart is the usual range.