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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.
Supporting Angled Flush Beams
Learn how to support the angled beams of a ground level deck with your support posts.
Building a Flat Roof Deck
Occasionally, a project is presented where a deck will be built over a flat roof of a house or a garage...
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.
10 Common Deck Building Mistakes & How to Avoid Them
Building a deck can be a complicated process. Learn how to avoid falling into common deck building pitfalls with tips and advice from the experts at Decks.com.
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" | |
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.
Building a Round or Curved Deck
Learn how to build a curved deck using standard wood-framing materials. Composite decking material is more flexible for curved decks than wood.
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.
Introduction to Decking
Spacing between deck boards provides several critical functions, such as drainage & drying. Learn how to space and stagger deck boards at Decks.com.
Tile decking
Installing tile over a standard deck frame in an exterior environment is a recipe for trouble.
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