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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" | |
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How to Decorate Deck Support Columns
Browse some examples of decorative deck support posts for tall decks.
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.
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.
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.
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.
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.
More Helpful Resources
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
Create a free account and get instant & exclusive access to all that Decks.com has to offer:
|
1,000+ How-To articles |
|
80+ Free Deck Plans |
|
Deck Planning Calculators |
|
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 | 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" | |
SaveHow to Decorate Deck Support Columns
Browse some examples of decorative deck support posts for tall decks.
Deck building tools
As with any professional job, having the right tools can make all the difference.
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.
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.
Tile decking
Installing tile over a standard deck frame in an exterior environment is a recipe for trouble.
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.
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