Deck Footing Spacing Chart: How Far Apart Should Footings Be?
Deck footings support the entire structural load of a deck. While homeowners often focus on footing size and depth, footing spacing is equally important because it directly affects beam spans, post locations, structural loads, and overall deck performance.
Improper footing spacing can lead to oversized beams, excessive structural costs, failed inspections, or unsafe load distribution. Proper spacing creates an efficient foundation system that safely supports the deck while minimizing unnecessary materials.
This guide explains how deck footing spacing works, what determines footing locations, and why there is no single spacing rule that applies to every deck.
Most residential deck footings are spaced between 6 and 10 feet apart, but actual spacing depends on beam size, beam span, post spacing, footing loads, soil conditions, and local code requirements.
Quick Answer: How Far Apart Should Deck Footings Be?
Most deck footings are spaced approximately:
- 6–8 feet apart for smaller residential decks
- 8–10 feet apart for many standard deck designs
- 10+ feet apart only when larger beams and engineered designs are used
There is no universal footing spacing requirement because spacing is determined by the structural design of the deck.
Footing spacing is typically controlled by beam spans and post spacing rather than deck size alone.
The Backyard Standard Footing Spacing Framework
Five primary factors determine footing spacing on residential decks.
| Factor | Influence on Spacing |
|---|---|
| Beam Size | Very High |
| Post Spacing | Very High |
| Deck Loads | High |
| Soil Capacity | Moderate |
| Local Code Requirements | Moderate |
Most homeowners assume footing spacing is determined by deck dimensions. In reality, beam design usually controls footing placement.
Why Footing Spacing Matters
Footing spacing affects nearly every structural component above the foundation.
Changing footing locations can affect:
- Beam sizes
- Post spacing
- Footing diameter
- Concrete volume
- Material costs
- Labor requirements
- Inspection approval
Efficient footing layouts often reduce both framing costs and foundation costs.
Footing Spacing vs Post Spacing
Many homeowners use these terms interchangeably, but they are not always identical.
In most residential deck designs, each footing supports a post, which means footing spacing and post spacing are often very similar.
However, some structural configurations may include multiple posts, specialty brackets, or engineered systems that alter this relationship.
Related: Deck Post Spacing Chart
Typical Residential Deck Footing Spacing
| Spacing Range | Typical Use |
|---|---|
| 6 Feet | Smaller beams, higher loads |
| 8 Feet | Common residential decks |
| 10 Feet | Larger beams, lighter load conditions |
| 12+ Feet | Engineered designs only |
Spacing beyond 10 feet often requires significantly larger beams and may increase overall project costs even if fewer footings are installed.
Why More Footings Are Not Always Better
A common misconception is that adding more footings automatically creates a stronger deck.
While additional footings can reduce beam spans, they also increase:
- Excavation
- Concrete volume
- Hardware requirements
- Labor costs
- Foundation costs
The most efficient design usually balances footing count with beam sizing and post spacing.
The goal is not to maximize footing count. The goal is to create an efficient load path from the deck framing into the soil.
What Determines Footing Locations?
Footings are generally located where structural loads are transferred into the ground.
Common factors influencing footing placement include:
- Beam locations
- Post locations
- Stair attachment points
- Concentrated loads
- Hot tubs
- Outdoor kitchens
- Roof structures
Large concentrated loads frequently require additional footings beyond what would normally be required for a standard deck.
Footing Spacing and Beam Size Work Together
Footing spacing and beam sizing are directly connected.
As footing spacing increases:
- Beam spans increase
- Beam loads increase
- Beam sizes often increase
Many homeowners attempt to reduce footing count without realizing that larger beams may offset any savings.
Related: Deck Beam Span Chart
Common Footing Spacing Mistakes
Using One Chart for Every Deck
There is no universal footing spacing chart that applies to every deck design.
Ignoring Beam Design
Beam sizing often controls footing spacing more than deck dimensions.
Assuming Fewer Footings Always Save Money
Larger beam requirements can offset footing savings.
Ignoring Soil Conditions
Weak soils may require larger footings or alternative layouts.
Deck Footing Spacing by Deck Size
Deck size influences footing spacing, but not in the way many homeowners expect.
Larger decks do not automatically require wider footing spacing. In many cases, larger decks require additional beams and additional footings to maintain safe structural loads.
| Deck Size | Typical Footing Count | Typical Spacing Range |
|---|---|---|
| 10×10 | 4 | 6–8 Feet |
| 12×12 | 4–6 | 6–8 Feet |
| 12×16 | 6–8 | 6–10 Feet |
| 16×20 | 8–12 | 6–10 Feet |
| 20×20 | 10–16 | 6–10 Feet |
Actual spacing depends on beam design, post locations, and structural loading conditions.
Deck Footing Spacing by Beam Size
Beam design is often the single biggest factor controlling footing spacing.
Larger beams can generally span farther between posts, allowing greater footing spacing.
Footing spacing should never be selected independently from beam design. The two systems must work together.
Before finalizing footing locations, review the Deck Beam Span Chart.
How Soil Conditions Affect Footing Spacing
Soil conditions affect how loads are transferred into the ground.
In some cases, weaker soils may require:
- Larger footing diameters
- Additional footings
- Shorter spans between supports
- Engineering review
| Soil Condition | Potential Impact |
|---|---|
| Dense Gravel | Minimal |
| Stable Loam | Minimal |
| Clay | Moderate |
| Sandy Soil | Moderate |
| Rocky Soil | High |
| Fill Material | High |
Weak soils often require foundation adjustments even when deck dimensions remain unchanged.
How Footing Spacing Affects Project Cost
Footing spacing directly affects both foundation costs and framing costs.
Wider spacing generally reduces:
- Excavation requirements
- Concrete volume
- Footing count
However, wider spacing may also require:
- Larger beams
- More expensive framing lumber
- Additional engineering review
The lowest-cost design is not always the design with the fewest footings.
Related: Deck Footing Cost
Example Footing Layout: 12×12 Deck
A typical 12×12 deck may use:
- 4 footings
- One beam
- Approximately 6–8 feet between footings
Actual spacing varies based on beam sizing and local code requirements.
Example Footing Layout: 12×16 Deck
A typical 12×16 deck often uses:
- 6 footings
- One or two beams
- Approximately 6–10 feet between footings
Larger spans may require upgraded beam sizes.
Example Footing Layout: 16×20 Deck
A typical 16×20 deck may require:
- 8–12 footings
- Multiple beam lines
- Additional structural support locations
Large decks often require more foundation planning than homeowners initially expect.
The Backyard Standard Footing Spacing Risk Assessment
Low Risk
- Ground-level deck
- Stable soil
- Standard residential loads
- Simple rectangular layout
Moderate Risk
- Elevated deck
- Large spans
- Clay or sandy soils
- Complex layouts
High Risk
- Steep slopes
- Fill material
- Hot tubs
- Outdoor kitchens
- Roof structures
Higher-risk projects often benefit from professional design review before construction begins.
Deck Footing Planning Toolkit
Recommended Deck Layout Tools
Accurate footing spacing starts with accurate layout. These tools can help homeowners plan footing locations, verify spacing, and improve foundation accuracy before excavation begins.
Bosch Blaze GLM165-40 Laser Distance Measure
Useful for footing layouts, beam locations, and post spacing measurements.
View Bosch Blaze Laser Distance Measure →
DEWALT 25-Foot Tape Measure
Essential for verifying footing spacing and structural layouts.
String Line & Stakes Kit
Helpful for establishing straight footing lines and accurate beam locations.
View String Line & Stakes Kit →
Johnson Torpedo Level
Useful for checking footing and post alignment during construction.
Simpson Strong-Tie ABA Adjustable Post Base
Creates the connection between deck posts and footings while helping protect posts from moisture.
View Simpson Strong-Tie ABA Post Base →
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Frequently Asked Questions
How far apart should deck footings be?
Most residential deck footings are spaced between 6 and 10 feet apart, although actual spacing depends on beam design, loads, soil conditions, and local code requirements.
Can deck footings be spaced 12 feet apart?
Sometimes, but spacing beyond 10 feet often requires significantly larger beams and may require engineering review.
Does footing spacing affect beam size?
Yes. Wider footing spacing generally increases beam span requirements and often requires larger beams.
Is footing spacing the same as post spacing?
In many residential decks they are similar, but footing spacing and post spacing are not always identical.
Do larger decks require wider footing spacing?
Not necessarily. Larger decks often require additional footings rather than wider spacing.
Does soil type affect footing spacing?
Yes. Poor soil conditions may require larger footings, additional footings, or different structural layouts.
Sources & Technical References
The Backyard Standard reviews technical guidance from recognized building-code and deck-construction organizations when developing structural planning resources.
Related Deck Building Guides
Deck Footing Calculator
Estimate footing count, concrete volume, and foundation requirements.
Deck Footing Size Chart
Understand footing diameter, depth, and structural requirements.
Deck Post Spacing Chart
Learn how post spacing affects deck structure and beam design.
Deck Beam Span Chart
Understand beam sizing and allowable spans.
Deck Footing Cost
Learn how footing size, depth, and soil conditions affect project budgets.
Deck Framing Cost
Understand structural framing costs and planning considerations.
Final Assessment
Deck footing spacing is one of the most important foundation design decisions in any deck project. Proper spacing creates an efficient load path from the deck structure into the soil while balancing footing count, beam size, and overall project cost.
Biggest Spacing Driver: Beam Design
Most Common Mistake: Assuming One Spacing Rule Applies to Every Deck
Best Cost-Saving Strategy: Optimize Footing Count and Beam Size Together
Best Planning Tool: Deck Footing Calculator
Best Supporting Resource: Deck Beam Span Chart
