40 psf live · 10 psf dead · L/360 · No. 2
Deck Beam Spans
Maximum deck beam span by beam size and the total joist span the beam carries (joists framing one side only).
Source: DCA6 — Prescriptive Residential Wood Deck Construction Guide, 2015 (based on 2015 IRC) — Table 2 (deck joists) and Table 3A (deck beams). Published by American Wood Council.
Southern Pine
| Beam size | ≤ 6′ joist | ≤ 8′ joist | ≤ 10′ joist | ≤ 12′ joist | ≤ 14′ joist | ≤ 16′ joist | ≤ 18′ joist |
|---|---|---|---|---|---|---|---|
| 2-2x6 | 6′-8″ | 5′-8″ | 5′-1″ | 4′-7″ | 4′-3″ | 4′-0″ | 3′-9″ |
| 2-2x8 | 8′-6″ | 7′-4″ | 6′-6″ | 5′-11″ | 5′-6″ | 5′-1″ | 4′-9″ |
| 2-2x10 | 10′-1″ | 8′-9″ | 7′-9″ | 7′-1″ | 6′-6″ | 6′-1″ | 5′-9″ |
| 2-2x12 | 11′-11″ | 10′-4″ | 9′-2″ | 8′-4″ | 7′-9″ | 7′-3″ | 6′-9″ |
| 3-2x6 | 7′-11″ | 7′-2″ | 6′-5″ | 5′-10″ | 5′-5″ | 5′-0″ | 4′-9″ |
| 3-2x8 | 10′-7″ | 9′-3″ | 8′-3″ | 7′-6″ | 6′-11″ | 6′-5″ | 6′-1″ |
| 3-2x10 | 12′-9″ | 11′-0″ | 9′-9″ | 8′-9″ | 8′-3″ | 7′-8″ | 7′-3″ |
| 3-2x12 | 15′-0″ | 13′-0″ | 11′-7″ | 10′-6″ | 9′-9″ | 9′-1″ | 8′-7″ |
Douglas Fir-Larch, Hem-Fir, Spruce-Pine-Fir
| Beam size | ≤ 6′ joist | ≤ 8′ joist | ≤ 10′ joist | ≤ 12′ joist | ≤ 14′ joist | ≤ 16′ joist | ≤ 18′ joist |
|---|---|---|---|---|---|---|---|
| 2-2x6 or 3x6 | 5′-2″ | 4′-5″ | 3′-11″ | 3′-7″ | 3′-3″ | 2′-10″ | 2′-6″ |
| 2-2x8 or 3x8 | 6′-7″ | 5′-8″ | 5′-1″ | 4′-7″ | 4′-3″ | 3′-10″ | 3′-5″ |
| 2-2x10 or 3x10 | 8′-1″ | 7′-0″ | 6′-3″ | 5′-8″ | 5′-3″ | 4′-10″ | 4′-5″ |
| 2-2x12 or 3x12 | 9′-5″ | 8′-2″ | 7′-3″ | 6′-7″ | 6′-1″ | 5′-8″ | 5′-4″ |
| 4x6 | 6′-2″ | 5′-3″ | 4′-8″ | 4′-3″ | 3′-11″ | 3′-8″ | 3′-5″ |
| 4x8 | 8′-2″ | 7′-0″ | 6′-3″ | 5′-8″ | 5′-3″ | 4′-11″ | 4′-7″ |
| 4x10 | 9′-8″ | 8′-4″ | 7′-5″ | 6′-9″ | 6′-3″ | 5′-10″ | 5′-5″ |
| 4x12 | 11′-2″ | 9′-8″ | 8′-7″ | 7′-10″ | 7′-3″ | 6′-9″ | 6′-4″ |
Note: DCA6 — Prescriptive Residential Wood Deck Construction Guide, 2015 (based on 2015 IRC) — Table 2 (deck joists) and Table 3A (deck beams) (American Wood Council).