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" |

How to Decorate Deck Support Columns
Browse some examples of decorative deck support posts for tall decks.
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Learn how to support the angled beams of a ground level deck with your support posts.
Building a Flat Roof Deck
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Decking Patterns
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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" |

How to Decorate Deck Support Columns
Browse some examples of decorative deck support posts for tall decks.
How to Decorate Deck Support Columns
Browse some examples of decorative deck support posts for tall decks.
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Explore Articles by Topic

Footings
Information related to installing frost footings for decks

Framing
Learn structural framing methods

Decking
Learn about wood and composite decking materials

Stairs
An in-depth look at the complex issue of how to build stairs

Railings
How to install guardrails and handrails to meet IRC code

Features
An overview on water drainage, benches, planters and lights

Design
The basics of deck design

Planning
Learn about permits and working with contractors

Porches & Patios
Build a covered deck to enjoy all seasons

Ledger
Proper attachment techniques

Care
Maintain your deck to maintain your investment

Materials
An overview on water drainage, benches, planters and lights