Ultimate Deck Beam Span Tables: Free Download & Calculator

Understanding Deck Beam Span Tables: A Comprehensive Guide

Deck Beam Span Chart (2026): Maximum Spans, Post Spacing & Framing Rules
Deck Beam Span Chart (2026): Maximum Spans, Post Spacing & Framing Rules

Deck beam span tables are essential tools for engineers, architects, and builders, providing a quick and reliable way to determine the appropriate beam size for a given span. These tables are based on extensive calculations and tests, ensuring that the beams selected can safely support the intended loads. In this article, we will delve into the world of deck beam span tables, exploring their purpose, how to use them, and the factors influencing their data.

Patio Roof Maximum Beam & Rafter Spans
Patio Roof Maximum Beam & Rafter Spans

What are Deck Beam Span Tables?

Deck beam span tables, also known as joist span tables, are lookup tables that list the maximum allowable spans for various beam sizes, subject to specific loading conditions. They are designed to help engineers and builders select the right beam size for a given span, ensuring that the structure can safely support the anticipated loads. These tables are typically provided by beam manufacturers and are based on standard loading conditions, such as those outlined in building codes like the American Institute of Steel Construction (AISC) or the American Concrete Institute (ACI) codes.

Deck Beam & Header Span Table | Decks.com
Deck Beam & Header Span Table | Decks.com

How to Use Deck Beam Span Tables

Using a deck beam span table is a straightforward process. Here's a step-by-step guide:

Deck Beam Span Chart: How Far Can a Deck Beam Span? - Fine Homebuilding
Deck Beam Span Chart: How Far Can a Deck Beam Span? - Fine Homebuilding
  • Identify the loading condition, such as live load (LL) and dead load (DL), and any applicable load combinations, as specified in the relevant building code.
  • Determine the span you want to cover with the beam. This is typically the distance between two supports, such as the center-to-center distance between two joists.
  • Locate the appropriate table for the beam material (e.g., steel, wood, or composite) and the loading condition you've identified.
  • Find the beam size that corresponds to your span in the table. The table will list the beam sizes in ascending order, with the maximum allowable span for each size.
  • Select a beam size that has a maximum allowable span equal to or greater than your required span. It's always a good idea to choose a beam that is slightly oversized to account for any unexpected loads or variations in the structure.

Here's an example of a simple deck beam span table for steel joists with a live load of 40 psf and a dead load of 20 psf:

Beam Size (in) Maximum Allowable Span (ft)
6 6
8 8
10 10
12 12
14 14
16 16
Better Deck Piers
Better Deck Piers

Factors Influencing Deck Beam Span Tables

Several factors influence the data in deck beam span tables. Understanding these factors can help you make more informed decisions when selecting beams:

  • Material: The strength and stiffness of the beam material significantly impact its maximum allowable span. Steel beams, for example, can span further than wood beams of the same size due to their higher strength-to-weight ratio.
  • Loading conditions: The applied loads, such as live loads and dead loads, determine the beam's deflection and stress. Heavier loads result in shorter maximum allowable spans.
  • Support conditions: The type of support, such as simple, continuous, or cantilever, affects the beam's deflection and stress. Continuously supported beams, for example, have shorter maximum allowable spans than simply supported beams.
  • Beam depth: Deeper beams have a larger cross-sectional area, which increases their strength and stiffness. As a result, deeper beams can span further than shallower beams of the same width.
  • Beam spacing: The spacing between beams influences the overall deflection of the deck or floor system. Narrower beam spacing results in shorter maximum allowable spans for the individual beams.
the table shows the number and types of lumber span tables for each type of table
the table shows the number and types of lumber span tables for each type of table

Custom Deck Beam Span Tables

While standard deck beam span tables are useful for many applications, some projects may require custom tables. For example, you might need to account for unique loading conditions, support conditions, or beam materials. In such cases, it's essential to consult with a structural engineer who can create a custom table tailored to your project's specific needs.

Deck Beam Span Chart: How Far Can a Deck Beam Span? - Fine Homebuilding
Deck Beam Span Chart: How Far Can a Deck Beam Span? - Fine Homebuilding
an image of the measurements for wooden beams
an image of the measurements for wooden beams
an image of a wooden table being built
an image of a wooden table being built
a wooden table with measurements for the top and bottom part, including an insulated base
a wooden table with measurements for the top and bottom part, including an insulated base
a table with numbers and times for each type of item in the text below it
a table with numbers and times for each type of item in the text below it
DIY Deck Part 1: Planning, Framing and Installing Deck Board - Fun Home Building
DIY Deck Part 1: Planning, Framing and Installing Deck Board - Fun Home Building
Tutorial for Understanding Loads and Using Span Tables - American Wood Council
Tutorial for Understanding Loads and Using Span Tables - American Wood Council
7+ Best Wood Deck Beam Calculator Collection
7+ Best Wood Deck Beam Calculator Collection
Good - A diagram illustrating correct and incorrect methods of connecting a deck beam to a supporting post in deck framing. It focuses on post-to-beam connections. Key Features: * Title: \
Good - A diagram illustrating correct and incorrect methods of connecting a deck beam to a supporting post in deck framing. It focuses on post-to-beam connections. Key Features: * Title: \
Small House Floor Joist Spacing | Floor Joist Span Table | Floor Framing
Small House Floor Joist Spacing | Floor Joist Span Table | Floor Framing
DIY Truss Beam Farmhouse Style Table and Benches (Restoration Hardware Inspired)
DIY Truss Beam Farmhouse Style Table and Benches (Restoration Hardware Inspired)
a table with numbers and measurements for the flooring options in each room, including
a table with numbers and measurements for the flooring options in each room, including
The Science of Simple Spans
The Science of Simple Spans
a wooden deck with an electrical outlet connected to it and the house in the background
a wooden deck with an electrical outlet connected to it and the house in the background
the parts of a deck and how they are used to build it in your home
the parts of a deck and how they are used to build it in your home
Deck Joist Span Explained
Deck Joist Span Explained
How to Install 2x8 Deck Beams
How to Install 2x8 Deck Beams
an image of a table with numbers and measurements for different types of electrical equipment in it
an image of a table with numbers and measurements for different types of electrical equipment in it
the parts of a wooden table and bench
the parts of a wooden table and bench
Floor Joist Span Tables to set your joists
Floor Joist Span Tables to set your joists

Conclusion

Deck beam span tables are invaluable tools for engineers, architects, and builders, enabling them to quickly and accurately select the appropriate beam size for a given span. By understanding how to use these tables and the factors influencing their data, you can make informed decisions that ensure the safety and longevity of your structures. Always remember that these tables are guidelines, and it's essential to consult with a structural engineer for complex or unique projects.