How far can you cantilever a deck joist?

Asked By: Shamaila Mallou | Last Updated: 30th January, 2020
Category: business and finance construction industry
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Joist Cantilevers
According to the new span tables and IRC provisions, cantilevers can extend up to one-fourth the backspan of the joist. This means that joists, such as southern pine 2x10s at 16 inches on-center, spanning 12 feet are allowed to cantilever up to an additional 3 feet (see illustration, below).

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People also ask, how far can you cantilever a 2x8 deck joist?

If the code span tables allow a 2x8 to span 12 feet, then the cantilever can be 3 feet.

Secondly, how far can decking overhang? Allow for Sufficient Overhang of Decking A one to two inch overhang beyond the outer fascia board is sufficient. This means the installed deck boards should have at least 1.75 to 2.75” overhang before the fascia is installed.

Beside above, how far can you cantilever a 2x6 deck joist?

Looking at the table below, we see that 2x6 floor joists can be cantilevered up to 2 feet and 6 inches (2'-6") when the joists are spaced 16" apart.

How far can a beam overhang a post?

Beams are permitted to cantilever past the end posts up to one-quarter of the beam span between posts. I like to use this provision when sizing beams. Often I can reduce the span between posts slightly by cantilevering the beam.

38 Related Question Answers Found

How much can a 2x8 cantilever?

Deck Joist Cantilever Rules and Limits
Joist Spacing (o.c.) 24"
Douglas Fir-Larch, Hem-Fir, Spruce-Pine-Fir 2x6 1'-2"
2x8 2'-2"
2x10 2'-9"
2x12 3'-3"

How far can you cantilever a 2x10 deck joist?

Joist Cantilevers
According to the new span tables and IRC provisions, cantilevers can extend up to one-fourth the backspan of the joist. This means that joists, such as southern pine 2x10s at 16 inches on-center, spanning 12 feet are allowed to cantilever up to an additional 3 feet (see illustration, below).

Can I use 2x6 for deck joists?

2x6 joists should only be used on ground-level decks that do not require, and will not provide for, any guards. Most decks use 16" on center spacing for joists. Most decking is not strong enough to support longer spans than 16".

How far can a 2x10 span without support?


When supporting joists that span 12 feet with no overhang beyond the beam, a double ply beam can span in feet a value equal to its depth in inches. A double 2x12 beam can span 12 feet; a (2) 2x10 can span 10 feet and so on.

How far can a triple 2x6 beam span?

A triple 2x6 beam over a span of 10' feet should be more than sufficient for normal deck loads.

Can 2x4 be used as deck joist?

2x4s are never ok for floor joists! 2x6 is iffy and may not meet minimum code. I agree with Marksr, that 2x6 would be minimal. Use a 4x6 rather than 2-2x6's for your beam.

Can you attach a deck to a cantilever?

Don't attach to a cantilever.
The entire load of the ledger is placed on the nails holding that band joist to the end grain of the house joists. If you have a cantilever, either build a freestanding deck or run the deck joists through the cantilever so they bear on the house wall or foundation.

What size lumber can span 20 feet?

Re: 20 foot clearspan beam size
In that case, you need something like a 12-16" GLULAM or LVL to span the 20' and can use simple 2x8-10 dimensional lumber 16"OC as floor joists.

What is the maximum span for a 2x6 floor joist?


Max. Live Load 30 lbs/ft2 (1436 N/m2)
Maximum Span (ft - in)
Nominal Size (inches) Joist Spacing Center to Center (inches) Lumber Grade
2 x 8 12 15' - 10"
16 14' - 5"
24 12' - 4"

How much weight can a 2x6 support horizontally?

The type of load in question will also determine how much weight a 2x6 can hold on edge. For example, a 2x4 lumber may hold a 4-cylinder engine comfortably but may not hold a bigger one. On the other end, a 2x6 can support a V8 engine of between 600 – 700 lbs.

What size wood should I use for decking frame?

Wood is the usual material used for decking. The lumber should be pressure treated to avoid rot and decay. Some of the most common wood used are cedar, redwood, fir and pine. There are decks that use concrete posts for support but wooden posts are the usual.

How many footings do I need for a deck?

For an attached 12 x 12' deck, you'll need at least 3 footings, plus at least 2 more if you're planning on building stairs with it. If your deck will be a different size, it's easy to figure out how many you'll need.

How far can you span a 2x6 Rafter?

The table states that 2 X 6 rafters spaced 16 inches on center (o.c) can span a maximum distance of 13 feet 5 inches. Another option are 2 X 8 rafters spaced 24 inches o.c.

How do you level deck joists?


  1. Check the installed beams and ledger boards on which you'll set the joist.
  2. Crouch down so you're eye level with the ledger board and beams, and look at the top edge.
  3. Don safety gear.
  4. Lay out one joist on the far right and far left of the deck; the outside joist should be as straight as possible.

What size should a deck ledger board be?

As a general rule, you should use the same size of board for the ledger as you plan to use for the joists. You can use a larger board, however, if it allows for a better connection to the house framing. Calculate the length as 3 inches less than the width of the deck framing.

What is cantilever coping?

Cantilevered coping is a poured-in-place bull nose concrete edge that extends around the perimeter of the pool. Many pool contractors include cantilevered coping in their base packages, so it is important to become familiar with it along with other pool coping options.