Loading

Create a free account and get instant & exclusive access to all that Decks.com has to offer:

Checkmark 1,000+ How-To articles
Checkmark 80+ Free Deck Plans
Checkmark Deck Planning Calculators
Checkmark Free & Simple Deck Design Tool

Deck Joist Cantilever Rules and Limits

The distance your joists can safely cantilever or overhang a drop beam is determined by the size of the joists, the wood type and grade of the lumber and the spacing between joists. Many building departments limit joist cantilevers to 24" maximum. Generally, you should use at least five framing nails to attach the rim joist to the ends of your joists. It's highly recommended to always contact your local code department to ensure all code and safety requirements are being met before building any decking structure.

The American Wood Council states that cantilevers are limited to 1/4 the span of the joists. 

 Joist Spacing (o.c.)  12"16"24" 
 Species Size Allowable Overhang
 Southern Pine 2x61'-0"1'-1"1'-4"
 2x81'-10" 2'-0" 2'-4"
 2x10 3'-1"3'-5"2'-10"
 2x124'-6"4'-2"3'-4"

 Douglas Fir-Larch,

Hem-Fir,

Spruce-Pine-Fir

 2x611"1'-0"1'-2"
2x8 1'-8"1'-10"2'-2"
2x10 2'-10"3'-2"2'-9"
2x12 4'-4"3'-11" 3'-3"

 Redwood,

Western Cedars,

Poderosa Pine, Red Pine

 2x69"10"11"
2x8 1'-5" 1'-7"1'-9"
 2x102'-5"2'-7"2'-8"
 2x123'-7" 3'-9"3'-1"
 
Maximum allowable overhang cannot exceed 1/4 of the actual main span.
PinterestSave

Popular Framing Articles
Deck Support Columns

How to Decorate Deck Support Columns

Browse some examples of decorative deck support posts for tall decks.

Deck Framing

Building A Deck Over An Air Conditioner

Things to consider when building a deck near an air conditioning unit. You may want to relocate the AC unit if possible to avoid some problems.

Deck Framing

Access to Hot Tub Decks

How will you access the controls of your hot tub on your deck? Make sure you have space to open and operate control panels when designing your deck.

Next Step: Decking Articles
Decking Installation

Decking Patterns

Installing your decking at a 45-degree angle is a popular style for decks. This can be done to reduce decking seams or just for appearance.

Decking Installation

Best Time to Build a Deck

People often wonder when the best time to build a deck is. Learn why building a deck in winter or fall might be your best bet.

Decking Installation

Dos & Don'ts for Homeowners to Consider When Building a Deck

Your dream deck can take whatever shape you like. The trick is making it fit your budget and site conditions. While the deck doesn’t have to be built as a rectangle, there could be good reasons for doing just that.

Get more helpful resources delivered right to your inbox

Explore Articles by Topic

Create a free account and get instant & exclusive access to all that Decks.com has to offer:

Checkmark 1,000+ How-To articles
Checkmark 80+ Free Deck Plans
Checkmark Deck Planning Calculators
Checkmark Free & Simple Deck Design Tool
Deck Framing

Deck Joist Cantilever Rules and Limits

The distance your joists can safely cantilever or overhang a drop beam is determined by the size of the joists, the wood type and grade of the lumber and the spacing between joists. Many building departments limit joist cantilevers to 24" maximum. Generally, you should use at least five framing nails to attach the rim joist to the ends of your joists. It's highly recommended to always contact your local code department to ensure all code and safety requirements are being met before building any decking structure.

The American Wood Council states that cantilevers are limited to 1/4 the span of the joists. 

 Joist Spacing (o.c.)    12" 16" 24" 
 Species  Size  Allowable Overhang
 Southern Pine  2x6 1'-0" 1'-1" 1'-4"
 2x8 1'-10"  2'-0"  2'-4"
 2x10  3'-1" 3'-5" 2'-10"
 2x12 4'-6" 4'-2" 3'-4"

 Douglas Fir-Larch,

Hem-Fir,

Spruce-Pine-Fir

 2x6 11" 1'-0" 1'-2"
2x8  1'-8" 1'-10" 2'-2"
2x10  2'-10" 3'-2" 2'-9"
2x12  4'-4" 3'-11"  3'-3"

 Redwood,

Western Cedars,

Poderosa Pine, Red Pine

 2x6 9" 10" 11"
2x8  1'-5"  1'-7" 1'-9"
 2x10 2'-5" 2'-7" 2'-8"
 2x12 3'-7"  3'-9" 3'-1"
 
Maximum allowable overhang cannot exceed 1/4 of the actual main span.
PinterestSave

Popular Framing Articles
Deck Support Columns

How to Decorate Deck Support Columns

Browse some examples of decorative deck support posts for tall decks.

Deck Framing

Deck building tools

As with any professional job, having the right tools can make all the difference.

Deck Support Beams

Understanding Point Loads and Beam-to-Beam Framing

Learn why it is important to install your deck beam to beam connections over a support post and footing.

Next Step: Decking Articles
Decking Installation

Decking Patterns

Installing your decking at a 45-degree angle is a popular style for decks. This can be done to reduce decking seams or just for appearance.

Decking Installation

Tile decking

Installing tile over a standard deck frame in an exterior environment is a recipe for trouble.

Decking Removal

How to Demolish & Remove a Deck

At some point, it might become necessary to remove an old deck, due to age or condition. Learn more about what's involved in a deck demolition and removal project.

Get more helpful resources delivered right to your inbox

Explore Articles by Topic