Understanding Deck Flush Beam Span Charts: A Comprehensive Guide
When designing or building a deck, understanding the structural components and their capacities is crucial. One key aspect is the span of flush beams, which significantly impacts the deck's strength and stability. This guide delves into deck flush beam span charts, their importance, and how to interpret them.
What are Deck Flush Beams?
Flush beams, also known as joists, are horizontal structural members used in framing to span an open space and provide support for the decking material. They are typically made of lumber or engineered wood products and are placed perpendicular to the bearing points or supports.
Why Use Deck Flush Beam Span Charts?
Deck flush beam span charts are essential tools for deck builders and designers. They provide a quick and reliable way to determine the maximum allowable span for a given beam size and species, based on the load the beam will bear. This ensures the deck's structural integrity and longevity.

Importance of Following Span Charts
- Safety: Following span charts ensures the deck can safely support the intended load without excessive deflection or failure.
- Code Compliance: Building codes often reference span charts to ensure decks meet minimum strength requirements.
- Cost-Efficiency: Using the right beam size for the span reduces material waste and labor costs.
Interpreting Deck Flush Beam Span Charts
Deck flush beam span charts typically display beam sizes along the y-axis and beam spans along the x-axis. The chart's cells indicate the maximum allowable live load (in pounds per linear foot) for a given beam size and span. Here's how to read them:
| Beam Size (Nominal) | 2 ft | 4 ft | 6 ft | 8 ft | 10 ft |
|---|---|---|---|---|---|
| 2x8 | 40 | 30 | 20 | 15 | 10 |
| 2x10 | 60 | 45 | 30 | 20 | 15 |
| 2x12 | 80 | 60 | 40 | 30 | 20 |
In this example, a 2x10 beam can safely support a live load of 45 pounds per linear foot over a 4-foot span. However, it can only support 15 pounds per linear foot over a 10-foot span.
Factors Affecting Beam Span
Several factors can influence the beam span beyond the beam's size and species:

- Decking Material: Heavier decking materials (like composite or stone) require stronger beams with shorter spans.
- Load: The total load (dead load + live load) affects the beam's span.
- Support Conditions: Beams with proper bearing at both ends can span longer than those with intermediate supports.
Conclusion
Deck flush beam span charts are invaluable tools for designing safe, durable, and code-compliant decks. By understanding how to read and apply these charts, you can ensure your deck project's success. Always consult local building codes and consider hiring a professional if you're unsure about any aspect of your deck's design or construction.
More Details
03.01.2005 ... The span of a beam is dependent on a few variables: The grade and species of lumber, size of lumber and the load it carries.

Using the beam span table, select your beam lumber size. Where it intersects ... Deck w/Flush Beam. Page 3. Deck Post to Deck Beam Requirements. Deck Beam ...

In this ar- ticle, I'll focus on how to read the new maximum deck beam span tables in the ... a deck with a flush rim beam. Expanded 2021 IRC beam tables ...

20.07.2023 ... You need to refer to the joist span tables to properly size/space your joists, by species, to confirm that your 8' span is allowable, but should ...

Deck Beam Span Lengths (ft-in)[a,b] 60 Live Load or 70 Ground snow Load ... flush beam connection. f. Beam cantilevers are limited to the adjacent ...

BEAM SPAN. OPTIONAL. CANTILEVER. OPTIONAL. CANTILEVER. BEAM SPAN. DROPPED BEAM. FLUSH BEAM. BEAM SPAN TABLE. DECK JOIST SPAN LESS THAN OR EQUAL TO: BEAM.

Span charts for deck joists and beams in a variety of framing materials, including wood and steel.

Use Table 2B for joist framing from both sides. • Beam may overhang past the supporting post up to one-fourth the beam span as indicated in. Figure 3.

07.03.2015 ... Figure R507.5 Joists with Flush Beam | Building a deck, Deck, Deck ... Deck Beam Span Chart: How Far Can a Deck Beam Span? - Fine ...

... beam and 0.70 for a “flush” box beam. 12. This span chart should not be used for decks located in a hurricane zone (in hurricane zones table E125, E150, or ...

Maximum allowable spans for wood deck beams, as shown in Figure R507.5, shall be in accordance with Table R507.5. Beam plies shall be fastened with two rows of ...

sides; Multi-span decks are permitted to mix flush and dropped beams. Beam Size. • Beam size is based on its influence width and longest span length per Table 2 ...

• Table 507.5 is a new span table just for deck beams. • Section 507.5.1 and ... JOISTS ON FREE-STANDING DECK. WITH FLUSH BEAM. Page 12. 4101:8-5-01. 51.

Residential deck span chart from Aurora, CO. Includes joist & beam span tables, ledger connections, & post height guidelines for safe deck construction.

DECK BEAM SPAN LENGHTHa,b,g. (feet - inches). DEPTH of deck. 6. 8. 10. 12. 14. 16. 18 ... flush beam condition. JOIST. BEAM. POST. DROPPED BEAM. OPTIONAL ...

This code and deck beam span chart simplifies sizing deck beams for 2-ply and 3-ply built-up beams, ensuring proper construction and safety.

Joists to beams - Joist hangers required for flush connections. c. Ledger to dwelling framing (if proposed). TABLE 507.4. DECK POST HEIGHT. DECK ...

16.04.2025 ... You can also use Decks.com's Joist Span & Spacing Calculator to determine how long your deck joist should span. ... flush beams. What About ...

09.12.2022 ... Share your videos with friends, family, and the world.

The intent of this document is to provide guidance on joist spans, built-up beam sizes, and supporting column sizes for exterior wood decks. The following items ...
