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Wood Joist Span Table Reference Values

Lookup typical residential wood joist spans by species group, nominal size, and on-center spacing.

Author

Prof. Anna Kowalska

Woodworking editorial contributor

Polish biostatistician at the University of Warsaw, advancing Bayesian methods for clinical trial design

Reviewed for accuracy by

Dr. Emeka Nwosu

Woodworking content reviewer

Nigerian legal scholar with an SJD from Yale, focused on international trade law and African continental free trade agreements

Last updatedFebruary 22, 2026

PublishedFebruary 22, 2026

On this page

  1. All value pages
  2. Reference table
  3. FAQs
  4. Methodology and review
  5. Related conversions

Reference Value Index

This page lists 45 reference values for quick browsing and lookup.

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All Reference Values

Reference Table

Wood Joist Span Table reference values
Species GroupJoist SizeSpacing (in o.c.)Max Span
SPF No.22 × 61212 ft 2 in
SPF No.22 × 61610 ft 11 in
SPF No.22 × 6248 ft 11 in
SPF No.22 × 81215 ft 10 in
SPF No.22 × 81614 ft 1 in
SPF No.22 × 82411 ft 7 in
SPF No.22 × 101219 ft 3 in
SPF No.22 × 101617 ft 2 in
SPF No.22 × 102414 ft 1 in
SPF No.22 × 121222 ft 2 in
SPF No.22 × 121619 ft 10 in
SPF No.22 × 122416 ft 3 in
SPF No.22 × 141224 ft 6 in
SPF No.22 × 141621 ft 11 in
SPF No.22 × 142417 ft 11 in
Douglas Fir-Larch No.22 × 61212 ft 9 in
Douglas Fir-Larch No.22 × 61611 ft 5 in
Douglas Fir-Larch No.22 × 6249 ft 4 in
Douglas Fir-Larch No.22 × 81216 ft 6 in
Douglas Fir-Larch No.22 × 81614 ft 8 in
Douglas Fir-Larch No.22 × 82412 ft 1 in
Douglas Fir-Larch No.22 × 101220 ft 2 in
Douglas Fir-Larch No.22 × 101618 ft 0 in
Douglas Fir-Larch No.22 × 102414 ft 9 in
Douglas Fir-Larch No.22 × 121223 ft 2 in
Douglas Fir-Larch No.22 × 121620 ft 8 in
Douglas Fir-Larch No.22 × 122417 ft 0 in
Douglas Fir-Larch No.22 × 141225 ft 6 in
Douglas Fir-Larch No.22 × 141622 ft 10 in
Douglas Fir-Larch No.22 × 142418 ft 8 in
Southern Pine No.22 × 61213 ft 3 in
Southern Pine No.22 × 61611 ft 10 in
Southern Pine No.22 × 6249 ft 8 in
Southern Pine No.22 × 81216 ft 11 in
Southern Pine No.22 × 81615 ft 1 in
Southern Pine No.22 × 82412 ft 5 in
Southern Pine No.22 × 101220 ft 9 in
Southern Pine No.22 × 101618 ft 6 in
Southern Pine No.22 × 102415 ft 2 in
Southern Pine No.22 × 121223 ft 10 in
Southern Pine No.22 × 121621 ft 4 in
Southern Pine No.22 × 122417 ft 6 in
Southern Pine No.22 × 141226 ft 2 in
Southern Pine No.22 × 141623 ft 5 in
Southern Pine No.22 × 142419 ft 2 in

Frequently Asked Questions

Frequently asked questions for Wood Joist Span Table and its reference values.

What loads are these span values based on?

These values are typical references based on common residential assumptions around 40 psf live load and 10 psf dead load.

Why does spacing change allowable span?

Wider on-center spacing means each joist supports more floor area, which reduces allowable span for a given size and species.

Can I use this instead of local building code tables?

Use this as a planning tool only. Final joist spans must follow your local code, species grade stamp, and project loading conditions.

Why are species groups separated?

Different wood species have different strength and stiffness properties, so allowable spans differ even with the same joist size.

Methodology and Review

Each row on this page links to a value detail page derived from the same conversion data file as the main calculator and reference table. This reduces inconsistencies across page variants.

Editorial metadata and structured data are rendered across the converter page and linked value pages. Review policies are documented in our review process and editorial policy.