# How far can you span a ceiling joist?

## How far can you span a ceiling joist?

Joist spacing of 24 inches is allowed for spans between 16 to 20 feet using 2-inch by 10-inch lumber of these three grades.

**How far can a 2×10 span for a ceiling joist?**

2×10 floor joists can span up to 20′. However, this is for 12” o.c. spacing for live loads that are 30 psf. This is unrealistic because any living space or deck requires a joist that can support a 40 psf live load.

**How far will a 2×8 span for a ceiling joist?**

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.

### How far can a 2×6 span for a ceiling 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 span a 2×12 ceiling joist?**

A 2×12 with an E of 800,000 psi and Fb of 790 psi also works, since it can span 15 feet and 10 inches. Given a design span of 15 feet 1 inch and a 16 inch joist spacing, first determine which size lumber will work.

**How far can 3 2X10 span?**

Dimensional Lumber Deck Beam Span Chart

Joist Spans | ||
---|---|---|

Southern Pine | 3-2X10 | 8′-9″ |

3-2X12 | 10′-6″ | |

Douglas Fir-Larch, Hem-Fir, Spruce-Pine-Fir, Redwood, Cedars, Ponderosa Pine, Red Pine | 3X6 OR 2-2X6 | 3′-7″ |

3X8 OR 2-2X8 | 4′-7″ |

## What will a 2×10 span?

Douglas fir 2-by-10 joists graded as “Structural Select” allows joist spans up to 21 feet for a live load of 30 pounds per square foot when spaced 12 inches apart, 19 feet 1 inch for 16 inch spacing and 16 feet 8 inches for 24 inch spacing.

**How far can 2×12 ceiling joist span?**

15 feet and 10 inches

A 2×12 with an E of 800,000 psi and Fb of 790 psi also works, since it can span 15 feet and 10 inches. Given a design span of 15 feet 1 inch and a 16 inch joist spacing, first determine which size lumber will work.

**What is the maximum span for a 2×4 Rafter?**

A 2×4 can span a maximum of 6′ 7” when spaced 16” apart and used as a floor or deck joist. When used as a ceiling joist or a roof rafter, a 2×4 can span up to 7′ 3” spaced at 16”, and 6′ 4” when spaced 24” apart. Due to the small spans of 2x4s, they often are not used in horizontal load-bearing capacities.

### What is the standard spacing for ceiling joists and why?

Instead, the length of the ceiling joists varies from room to room, depending on each room’s measurements. Regardless of the size or length of joists, they do retain a standard spacing of 16 inches . The ability of the joists to support weight depends upon this spacing, and 16 inches provides sufficient support for most home ceiling types.

**What is the maximum span for a 2×10 floor joist?**

What is the maximum span for a 2×10 floor joist? Douglas fir 2-by-10 joists graded as “Structural Select” allows joist spans up to 21 feet for a live load of 30 pounds per square foot when spaced 12 inches apart, 19 feet 1 inch for 16 inch spacing and 16 feet 8 inches for 24 inch spacing.

**What are the two functions of ceiling joists?**

The ceiling beam, or ceiling joist, has two prime functions. The first is to tie the walls of a structure or a room together, effectively completing a box configuration. The second is, as the name implies, to support the ceiling of the structure, or room. Ceiling joist framing is undertaken after the walls are erected.

## How can I find a ceiling joist?

Use the tape measure to map the rough location of the next joist, roughly 16 or 24 inches away from the first, and tap the ceiling with your knuckles or sweep a stud finder over the area to pinpoint the joist’s location. Repeat for any other joists you need to locate.