# How far can joists span on a deck?

## 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.

## How far can a deck span without support?

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.

**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 apart should support beams be on a deck?**

How Far Apart Should You Space Deck Joists? The short answer: deck joists are typically spaced either 12 inches or 16 inches apart, on center. (On-center means the length from the center of one joist to the center of the next joist, rather than a gap from edge to edge).

### How do I calculate deck joist span?

So to span 10-feet use a 2×8. Another way for 16”o.c. is that a joist can span 1.5 times its thickness in feet – so, for a 2×8 calculate 1.5 x 8” = 12′ for the span. Regardless of the span, 2×6 joists are usually limited to ground-level decks without railings.

### 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.

**Is 4×2 OK for decking joists?**

4 x 2 Timber Rail / Joist These decking joists are the most common sized framing timber for decking. They provide a solid structure for fixing your decking boards too. When making your decking frame you should use a 400mm spacing between your timber joists.

**Can you build a deck with 2×4 joists?**

The short answer is yes. 2x4s can work for deck joists. 2x4s are the smallest dimensional option, making them great for low, ground-level decking if they’re spaced no further than 12” on center. “On center” is the term to measure from one joist to the next, starting from one center to the center of another.