RHS vs SHS Steel: Which One Should You Choose for Your Project?

When it comes to structural steel, two of the most commonly used types are RHS (Rectangular Hollow Section) and SHS (Square Hollow Section). Both are versatile, durable, and widely used in Australian construction. But when planning your project, the big question is: Should you choose RHS or SHS steel?

This guide breaks down the key differences, uses, and benefits so you can make the right choice.

What is RHS Steel?

RHS (Rectangular Hollow Section) is a type of structural steel with a rectangular shape. It’s manufactured in various sizes and thicknesses, making it suitable for heavy-duty structural applications.

Common RHS features include:

• Flat surfaces, which are ideal for joining and fabrication
• High strength in one axis (longer side)
• Wide availability in galvanised and non-galvanised finishes
  

Typical Uses:

• Beams and bridges
• Columns in large structures
• Load-bearing frames
• Industrial applications
  

What is SHS Steel?

SHS (Square Hollow Section) steel comes in a square shape with equal sides. It provides a balance of strength and aesthetics, making it popular in residential and commercial projects.

Common SHS features include:

• Symmetrical strength on all sides
• Easy to weld and fabricate
• Clean, modern appearance
• Available in sizes from 20 × 20 mm to 400 × 400 mm

Typical Uses:

• Posts and columns
• Exposed architectural elements
• Light to medium structural framing
• Steel-to-timber connections with SHS cleats
  

Key Differences Between RHS and SHS Steel

Factors to Consider Before Choosing

When deciding between RHS and SHS, consider:

1. Load Requirements
   • Heavy loads in one direction → RHS
   • Evenly distributed loads → SHS
     
2. Design & Aesthetics
   • Visible, modern look → SHS
   • Industrial, hidden framework → RHS
     
3. Budget
   
   • RHS can be more cost-efficient for specific load-bearing tasks
   • SHS is versatile and reduces wastage in balanced structures
     
4. Building Codes
   • Always ensure compliance with AS/NZS 1163 standards in Australia.
     

Common Sizes of RHS and SHS

• RHS sizes: From 50 × 25 mm to 400 × 300 mm, thicknesses up to 16 mm
  
• SHS sizes: From 20 × 20 mm to 400 × 400 mm, thicknesses up to 16 mm
  

Both are available in:
– Pre-galvanised steel
– Painted or raw finish
– Custom cutting from suppliers

Which One Should You Choose?

• Choose RHS if:
  • You need strength in one direction (like beams or bridges)
  • You’re working on industrial projects with heavy loads
    
• Choose SHS if:
  • You want a clean, modern look for visible structures
  • You need equal strength in both directions (like posts or supports)
    

👉 In many projects, both RHS and SHS are used together, depending on the load and design requirements.

Role of Cleats in RHS and SHS Connections

Whether you choose RHS or SHS, strong cleat connections are essential. For example:

• SHS cleats are perfect for steel-to-timber or column connections
• RHS cleats can be used in bridges, trusses, and heavy frames
  

High-quality cleats ensure:

• Faster installation
• Stronger joints
• Long-term durability
  

Cost Comparison: RHS vs SHS

Pricing depends on size, wall thickness, and galvanisation. On average in Australia:

• RHS steel: $30–$500 per length
• SHS steel: $15–$500 per length

💡 Pro Tip: For exposed projects, SHS may be slightly more expensive due to its architectural appeal.

Final Thoughts

Both RHS and SHS steel are excellent choices, but the right one depends on your project’s needs. If your design requires directional strength, RHS is the best option. If you want balanced strength and a modern finish, SHS is ideal.

And remember—no matter which steel you choose, pairing it with quality cleats ensures strong and safe connections.

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