Are Welded Shed Joints better than Bolted?
When constructing high tensile steel portal framed sheds, the choice between bolted brackets using plates and purlin bolts versus welded joints can significantly impact durability, cost, and performance. At Dinky Di Sheds, we advocate for bolted connections over welded joints, even when both methods involve pre-fabricated components supplied off-site. Here’s why bolted brackets are the superior choice for your next shed project.
1. Preserving the Integrity of High Tensile Steel
High tensile steel, commonly used in portal framed sheds for its strength (typically above 700 MPa yield strength), is highly sensitive to heat. Even when welded joints are pre-fabricated off-site in a controlled environment, the welding process still involves extreme temperatures (1,400–1,500°C for arc welding). This heat can weaken the steel in the heat-affected zone (HAZ), leading to:
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Softening: The tempered martensitic structure of high tensile steel may over-temper, reducing hardness and strength.
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Cracking Risks: Rapid cooling during welding can cause hydrogen-induced cracking or cold cracking, particularly in high tensile steel with higher carbon equivalent values.
Bolted brackets with plates and purlin bolts eliminate heat exposure entirely. By using pre-drilled, pre-fabricated components, you preserve the steel’s original properties, ensuring your shed maintains its structural integrity over time. This is especially critical for sheds in harsh Australian environments, like cyclone-prone regions, where material strength is essential.
2. Simpler and Faster On-Site Assembly
Both bolted and welded portal framed sheds can be pre-fabricated off-site, but the on-site assembly process differs significantly. Pre-fabricated welded sheds arrive as large, rigid sections that require precise alignment and often heavy machinery to position. Any misalignment during transport or installation can be difficult to correct without cutting and re-welding, which introduces the same heat-related risks.
Bolted brackets offer a more streamlined assembly process:
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Ease of Assembly: Pre-drilled plates and purlin bolts allow for quick and accurate connections using basic tools like an impact wrench.
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Adjustability: Bolted joints can be easily adjusted on-site to correct minor misalignments, ensuring a perfect fit without compromising the steel.
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Faster Erection: Bolting is faster than handling large welded sections, reducing on-site time. For example, a Dinky Di Sheds portal framed shed with bolted haunch and apex joints can be erected in days, even in remote areas like Toowoomba.
This efficiency saves time and reduces labor costs, making bolted sheds a practical choice for both professionals and DIY builders.
3. Flexibility for Future Modifications
Sheds often need adjustments over time—whether you’re adding a mezzanine floor, expanding the structure, or relocating it entirely. Pre-fabricated welded joints, while strong, are permanent and challenging to modify. Cutting a weld to make changes risks further weakening the steel and requires re-welding, which reintroduces heat-related issues.
Bolted brackets provide unmatched flexibility:
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Easy Disassembly: Need to relocate your shed? Unbolt the sections, transport, and reassemble with minimal hassle.
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Adjustable Design: Plates and purlin bolts allow for precise adjustments during assembly and future modifications without compromising the structure.
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Reusability: Bolted components support sustainability. Galvanized bolts and plates can be re-galvanized and reused, making your shed more eco-friendly.
4. Better Performance Under Dynamic Loads
Portal framed sheds, especially in regions like Toowoomba with variable weather, face dynamic loads from wind, temperature changes, and even seismic activity. Pre-fabricated welded joints, while rigid, are prone to fatigue and cracking under cyclic loading. Even a high-quality weld can develop micro-cracks over time, leading to potential failure.
Bolted brackets with plates and purlin bolts perform better under these conditions:
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Fatigue Resistance: Bolted joints handle cyclic loading more effectively, as the bolts can flex slightly without cracking, unlike the monolithic nature of welds.
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Friction Grip: High-strength bolts (e.g., galvanized friction-grip bolts) transfer loads through friction between plates, reducing stress concentrations that lead to failure.
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Maintenance: Bolts can loosen over time due to vibrations, but this is easily addressed with periodic checks and tightening—far simpler than repairing a cracked weld.
5. Cost-Effectiveness and Quality Control
Pre-fabricated welded sheds might seem cost-competitive claiming they also reduce on-site labor, but hidden costs can add up. Welding high tensile steel, even in a factory setting, requires non-destructive testing (e.g., ultrasonic or X-ray inspections) to ensure quality, which increases production costs. A subpar weld—whether due to human error or manufacturing oversight—can compromise the entire shed, and fixing it often means costly rework.
Bolted brackets offer a more reliable and cost-effective solution:
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Lower Overall Costs: The automated manufacturing of pre-drilled plates and bolts reduces production expenses compared to welding’s labor-intensive process.
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Consistent Quality: Bolts are pre-manufactured and tested for strength (e.g., AS 4100 specifies minimum bolt tension), ensuring consistent performance across every shed. You don’t have to worry about weld quality variability.
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Fewer Risks: Bolting eliminates the need for heat-related quality controls, making the process safer and less prone to defects.
6. ShedSafe™ Accredited Assurance
At Dinky Di Sheds, our bolted portal framed sheds are
ShedSafe™ Accredited, meeting rigorous Australian standards for safety and durability. The use of bolted brackets with plates and purlin bolts ensures compliance with these standards, giving you peace of mind that your shed is built to last—without the risks associated with welding high tensile steel.
Conclusion: Bolted Brackets Are the Smarter Choice
For high tensile steel portal framed sheds, bolted brackets using plates and purlin bolts outperform pre-fabricated welded joints in nearly every way. They preserve the steel’s strength, simplify and speed up on-site assembly, allow for future flexibility, perform better under dynamic loads, and save you money in the long run—all while meeting ShedSafe™ standards. Whether you’re in Toowoomba or beyond, choosing bolted connections ensures your shed is strong, adaptable, and built to withstand Australia’s toughest conditions.
Ready to build your high tensile steel shed with the best connection method?
Contact Dinky Di Sheds today to discuss your project and see how our fully bolted shed designs can work for you!
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Dinky Di Sheds Pty Ltd
Trading as Dinky Di Sheds
ABN
1800 785 224
Head office 226 Campbell St
Toowoomba 4350
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