## How far can a 6×2 joist span?

As previously mentioned, many factors can affect span measurements. A 2×6 joist can span anywhere between 8′ for Cedar and Redwood to 9′ for Pine and Fir at 16″ OC. 12″ OC yields longer spans, while 24″ OC allows shorter spans.

## How far can you span a joist?

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.

**What size joist do I need?**

For example, assume the clear span is 15 feet 6 inches. Round up to 16 and divide this span by 2, giving you 8. Next, add 2 to get the required joist depth. In this example, 8 + 2 = 10, so a 2×12 floor joist will be required (it’s important to use the actual lumber dimensions, not the nominal dimensions).

**What is maximum span for timber joist?**

Spacing (distance apart) of joists – centres

Size of joist mm | 400mm | 450mm |
---|---|---|

SPAN metres | SPAN metres | |

38 x 97 | 1.72 | 1.56 |

38 x 122 | 2.37 | 2.22 |

38 x 140 | 2.72 | 2.59 |

### Can I use 3×2 for floor joists?

NO! 3″ x 2″ joists can only span 1.41 metres when used as floor joists and this is at 400mm joist centres, any further apart and the span must be reduced even further.

### How far can a 2 6 span without support?

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.

**What is stronger 4×6 or 2 2×6?**

A 4×6 joist is theoretically stronger than a doubled 2×6 joist because it’s 1/2″ thicker, but the actual strength depends upon the knots and other inherent weaknesses of any particular piece of lumber (#2 lumber can have some nasty spike knots or large not-so-tight round knots or wane).

**How far can a 2X10 joist span without support?**

A 2×10 beam – made up of two 2x10s nailed together – can span up to 11′ without support beneath a deck that is 4′ wide. For a more normal-sized deck, the same beam can span 8′, supporting a deck that is 8′ wide.

## What do you need to know about floor joist span?

You need to measure the complete span of your floor joists, together with the distance between them (the ‘centres’) and the size of the timbers. This should be compared to the table.

## What should the spacing be on a ceiling joist?

Spacing Tables, such as those for rafters, floor joists and ceiling joists require the spacing of members to be known or selected in order to obtain the required size for a given span. Spacing should be interpreted as the centre to centre distance between adjacent parallel members.

**Do you have to include joist weight in span table?**

The dead loads shown at the top of span table above do not include the self weight of the joists, however, the joist self weights are included (in addition to the dead loads) in the calculations used to determine permissble clear spans. Timber to be covered, these span tables do not apply to timber which is fully exposed to the elements.

**How big should holes be in floor joists?**

Holes drilled at the neutral axis (centre line) are not to exceed 0.25 of the depth of a joist and are not to be less than three diameters (centre to centre) apart and are to be located between 0.25 and 0.4 of the span from the support. Solid timber strutting to be at least 38mm thick and be a minimum of three quarters of the joist depth.