When it comes to building a long-lasting, low-maintenance outdoor surface with ThruFlow™ panels, proper support structure and fastening methods are essential. Whether you’re building a dock, deck, walkway, or platform, understanding joist spans and choosing the right fasteners ensures the safety, stability, and durability of your project.
What Is a Joist Span?
A joist span refers to the distance between two structural supports—such as beams or posts—that a joist can bridge without sagging or failing. For decking with ThruFlow™ panels, following the correct joist span guidelines is critical for optimal performance.
Why Proper Joist Spacing Matters
Correct spacing:
- Prevents panel flex and sag
- Extends the lifespan of your ThruFlow™ decking
- Provides weight distribution and safety
- Ensures warranty compliance
Support Spans
| Size
(feet) |
1 x 3 | 1 x 4 | 2 x 3 | 2 x 4 | 1 x 5 | 4 x 4 |
| Support Span
(inches) |
18 | 16/24 | 18 | 16/24 | 15 | 16 |
| # of Fasteners | 6 | 8/6 | 6 | 16/12 | 10 | 32 |
For more detailed information on installation, please refer to our Installation Guide.
Recommended Fasteners for ThruFlow™
To get the most out of your ThruFlow™ perforated panels, we recommend 305/316 stainless steel fasteners.
Recommended Fasteners:
- Use #10 or #12 pan-head screws (minimum 2.5” long)
- Do not overtighten—leave a small gap to allow for expansion
- Use one screw per support span fastening point and each end
- For applications other than wood, a self-tapping/self-drilling fastener is recommended
Final Thoughts
Using the right joist spans and fasteners with your ThruFlow™ panels is not just about meeting specs—it’s about creating a safe, high-performance structure that stands the test of time. From residential docks to commercial boardwalks, these details ensure the lasting success of your build. Be sure to follow your local building codes and any guidelines set by your local authorities.
For more detailed installation instructions or help planning your next ThruFlow™ project, contact our team or visit our FAQ page