## How far can joists span on a deck?

16 inches

Decking boards span from joist to joist. If you use 5/4 decking, joists must be no farther apart than 16 inches. Decking made of 2x4s or 2x6s can span up to 24 inches. If you will run decking at an angle, you might need to put the joists closer together.

### What is the maximum span for a 2×8 deck joist?

Depending on various factors, the maximum span for a 2×8 floor joist is 16′ 6”. The maximum span for roof rafters is 23′ 9”. For headers, the maximum span is 11′ 2”. Finally, a single deck beam has a maximum span of 5′ 11” and double maxes out at 8′ 9”.

**How far can a 2×6 decking span without support?**

2-grade 2×6 joists can span up to 10 feet 9 inches from beam to beam when spaced the standard 16 inches apart with a maximum live load of 30 inches per square foot.

**Can a 2×8 span 16 feet?**

Span is determined by species, grade, dimensions, spacing, use, and load. A rule of thumb is 1.5 times a joist’s depth but in feet when spaced at 16” centers. In general, a 2×8 will span 1.5 x 8, so 12-feet. Based on all factors though, a 2×8 joist span is 7′-1” to 16′-6”, and a rafter 6′-7” and 23′-9”.

## What is the maximum span for a 2×10 deck joist?

Deck Joist Span Chart

Joist Spacing (o.c.) | 16″ | |
---|---|---|

Douglas Fir-Larch, Hem-Fir, Spruce-Pine-Fir | 2×8 | 11′-1″ |

2×10 | 13′-7″ | |

2×12 | 15′-9″ | |

Redwood, Western Cedars, Ponderosa Pine, Red Pine | 2×6 | 8′-0″ |

### What is the maximum span for 2×6 joist?

The maximum distance a 2×6 can span, according to the 2018 IRC, for a floor joist, is 12′-6”, ceiling joist 20′-8”, rafter 18′-0”, deck board 24”, deck joist 9′-11”, deck beam 8′-3”, and 6′-1” as for header. Always check the codes for determining factors or consult a Structural Engineer.

**How far can you cantilever a deck joist?**

Most cantilevers have a 3:1 ratio. The most common example of this you will find is a deck that attaches to a house that is 12 feet perpendicularly away from the house. The outer support beam must be no closer to the house than 9 feet (or, no more than 3 feet can hang over the outer beam unsupported).

**Can I use 2×6 for deck joists?**

2×6 joists should only be used on ground-level decks that do not require, and will not provide for, any guards. Similar to guards, if stairs are to be hung from the side of an upper-level deck, 2×10 as a minimum is recommended, as it will exceed the depth of the first step.

## What is maximum unsupported span for deck joists?

Most decks use 16″ on center spacing for joists. Most decking is not strong enough to support longer spans than 16″. Some builders reduce joist spacing to 12″ on center to strengthen the deck frame or to increase maximum allowable joist spans.

### How far can a deck joist span?

In general terms, joists spaced 16 inches on center can span 1.5 times in feet their depth in inches. A 2×8 up to 12 feet; 2×10 to 15 feet and 2×12 to 18 feet. The larger the deck, the larger the joists.

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