When it comes to building, one of the most important tools you’ll ever use is a span table. For those working with Duragal steel, knowing how to read and apply the Duragal span table is essential. Whether you’re a new builder, a DIY enthusiast, or a seasoned professional, understanding the secrets behind these tables will save you time, money, and mistakes.
This guide will break down the best Duragal span table secrets every builder must know in very easy-to-understand language. By the end, you’ll feel confident about using Duragal span tables in your next project.
What is a Duragal Span Table?
A Duragal span table is a reference chart provided by steel manufacturers that shows you the maximum span (distance between supports) that Duragal steel members can cover safely.
- Duragal steel: This is a type of hot-dip galvanized steel product manufactured to resist corrosion. It’s popular in construction, farming, fencing, sheds, and many DIY projects.
- Span table: Think of it like a safety manual. It tells you how far a beam, joist, or column can go without sagging or failing.
For example, if you’re using a Duragal C-section or RHS (Rectangular Hollow Section), the span table tells you exactly how far it can stretch between supports depending on load conditions.
Why Duragal Span Tables Are Important
Many new builders think they can “eyeball” a beam size or guess how strong a piece of steel will be. But here’s why you must use a span table:
- Safety – The wrong span can cause structural failure. No builder wants accidents on-site.
- Efficiency – Using the right size saves steel. Oversizing wastes money, undersizing risks collapse.
- Compliance – Building codes require proper use of span tables. Inspectors check this.
- Confidence – Knowing your spans means less second-guessing and faster decisions.
So, span tables are not just guidelines—they’re the law of the build.
The Basic Secrets of Duragal Span Tables
Here are the most important things builders should know:
1. Load Matters More Than Length
The same Duragal beam can span different distances depending on the load. For example:
- Light roof load → longer span possible
- Heavy floor load → shorter span only
Secret: Always check the load category (roof, floor, mezzanine, shed, etc.) before choosing the span.
2. Orientation Changes Everything
A Duragal section like an RHS or C-section has different strengths depending on how it’s placed.
- On the strong axis, it can carry more load.
- On the weak axis, the span is shorter.
Secret: Never assume. The table will always clarify the orientation.
3. Thickness and Size Rule the Game
Bigger and thicker sections = longer spans.
For instance:
- A 75x75x3.0 RHS will span further than a 65x65x2.5 RHS.
Secret: Don’t just look at the shape, look at the wall thickness too.
4. Duragal Has Unique Coating Benefits
Duragal steel is pre-galvanized during production. This makes it durable, but the coating thickness doesn’t affect the span—it affects corrosion resistance.
Secret: Use span tables for strength, but consider the coating for the environment (coastal, rural, urban).
5. Deflection is as Important as Strength
A beam might not break, but it could bend too much. Span tables include deflection limits, which stop floors from feeling bouncy or roofs from sagging.
Secret: Always check the deflection column in the span table, not just the strength column.
Reading a Duragal Span Table Step by Step
Many builders struggle the first time they look at a span table. Let’s make it super simple:
- Find the product type – RHS, SHS, C-section, or angle.
- Choose the size – e.g., 75x50x2.5.
- Check the load case – roof, floor, racking, or general.
- Read across to the span – this gives you the maximum spacing allowed.
- Confirm deflection limits – make sure it meets comfort and code.
Common Mistakes Builders Make with Span Tables
Even experienced builders sometimes misuse span tables. Here are the top mistakes:
- Using the wrong load type – mixing roof span values for floor spans.
- Forgetting wind loads – sheds and carports face high wind pressures.
- Ignoring connection strength – the beam might be fine, but weak joints can fail.
- Guessing instead of checking – never rely on memory; always double-check the table.
How Duragal Span Tables Save Money
Using span tables is not just
- Right-sizing members means no overspending on oversized steel.
- Reduced rework avoids costly mistakes.
- Optimized spans can reduce the number of supports needed.
Over time, this can save thousands of dollars on a project.
Secrets for Different Applications
Let’s break down where span tables really shine:
1. Sheds and Carports
Duragal is widely used here. Span tables help decide the size of rafters, columns, and purlins.
Tip: Wind classification (N1, N2, C1, etc.) affects allowable spans. Always check your wind rating.
2. Residential Decks
Builders love using Duragal RHS for deck bearers and joists.
Tip: Pay attention to live loads (people walking, furniture) vs. dead loads (self-weight). Span tables separate these.
3. Fencing and Gates
Posts and rails made from Duragal sections need correct spacing.
Tip: In soft soil or exposed sites, reduce spans for added safety.
4. Industrial and Farm Buildings
Large sheds, barns, and warehouses rely on Duragal span tables to size beams correctly.
Tip: Snow or equipment loads can drastically reduce maximum spans.
Duragal Span Table vs. Other Steel Span Tables
Why do many builders prefer Duragal?
- Pre-galvanized: No need for extra coating.
- Easier welding and fabrication: Cleaner finish.
- Consistency: Duragal products are standardized, making span tables reliable.
Compared to untreated mild steel, Duragal lasts longer and is safer for outdoor projects.
The Ultimate Builder’s Checklist for Using Duragal Span Tables
Here’s a quick checklist every builder can follow:
- ✅ Identify the right section size and shape.
- ✅ Confirm wall thickness.
- ✅ Match the correct load case.
- ✅ Read span limit AND deflection limit.
- ✅ Factor in wind, snow, or point loads.
- ✅ Double-check with building codes
Conclusion
The best Duragal span table secrets every builder must know come down to this:
- Always check the load type.
- Match the right section size.
- Don’t ignore deflection.
- Remember environmental conditions.
- Use span tables to save money and time.
Duragal span tables aren’t just numbers on paper—they’re your guide to safer, stronger, and smarter building.
So next time you’re starting a shed, deck, or industrial project, don’t guess. Reach for the Duragal span table and build with confidence.