Strut Channel Sizes Explained: Which Profile Do You Need for Your Project?

If you've never specified strut channel before, the options can look confusing fast. Two widths, two depths, two wall thicknesses, plain or slotted, pre-galvanised or hot dipped, 3m or 6m and that's before you add back-to-back or coloured finishes into the mix.

So, don't overlook the importance of understanding strut channel sizes in your upcoming projects.

Understanding strut channel sizes is crucial for selecting the right support solutions for your projects.

When considering strut channel sizes, it's important to understand the various options available to ensure you select the most suitable one for your needs. The right strut channel sizes can make a significant difference in your project's efficiency and effectiveness.

This guide cuts through it. By the end you'll know exactly which profile to order for your job.

What Is Strut Channel?

Choosing the correct strut channel sizes is essential for optimal support in any installation. The market offers a wide range of strut channel sizes to fit various applications, from light-duty tasks to heavy-duty structural needs.

Strut channel, also known as Unistrut, channel section, or cable management channel, is a pre-formed steel section used to support, brace, and hang equipment across a huge range of trades. Electricians use it to run cable tray. Plumbers and HVAC engineers use it to support pipework. Solar installers use it for panel frames. Mechanical contractors use it for pretty much everything else.

All strut channel sold by Direct Cutting is Unistrut compatible and manufactured to BS 6946:1988 standards, so it integrates with standard channel nuts, brackets, and fittings without any modification.

The Two Core Profiles: 41×21 and 41×41

Every standard strut channel is 41mm wide. The number that changes is the depth.

41×21mm - Half Depth Channel

The shallower of the two profiles. At 21mm deep, it's lighter, easier to handle in tight spaces, and lower cost per metre.

Best for:

• Light-duty cable containment runs
• Lightweight pipe support (small bore)
• Partition framing and secondary steelwork
• Applications where ceiling height or clearance is tight

Available in 1.5mm and 2.5mm wall thickness, in both plain and slotted, in 3m and 6m lengths.

41×41mm - Full Depth Channel

The standard workhorse. At 41mm deep, it carries significantly more load than the half-depth profile and is the default choice on most commercial and industrial installations.

Best for:

• Medium to heavy pipe support
• Cable tray primary support runs
• Structural framing and equipment mounting
• Solar panel sub-frames
• Any application where span or load is a factor

Also available in 1.5mm and 2.5mm wall thickness, plain or slotted, 3m or 6m, plus a hot dipped galvanised option for external or corrosive environments.

In many situations, the choice of strut channel sizes will dictate the overall structural integrity of your installation. Ensure you choose the right strut channel sizes to match your project's demands.

1.5mm vs 2.5mm Wall Thickness

Knowing the different strut channel sizes available will help you make informed decisions. Remember, not all strut channel sizes are created equal; the dimensions impact both performance and cost.

Wall thickness is where most people get caught out. Both profiles are available in 1.5mm and 2.5mm steel, and the difference matters.

Rule of thumb: If you're spanning more than 1.5m between supports, or hanging anything heavier than light cable, go 2.5mm. For internal light containment work on short spans, 1.5mm is fine and cheaper.

Additionally, understanding the various strut channel sizes will allow you to select the most economical option for your project, balancing performance and cost-effectiveness.

Plain vs Slotted: Which Do You Need?

Utilising the correct strut channel sizes is vital in ensuring that your installations meet industry standards and project specifications.

This is simpler than it sounds.

• Plain channel has a solid face. It's used where you need a clean surface for welding, where slots aren't needed, or where aesthetics matter.
• Slotted channel has a row of slots along the face, allowing channel nuts and fittings to be positioned anywhere along the length. It's the most versatile option and the one most commonly specified.

If in doubt, go slotted. It gives you full flexibility to position fixings anywhere along the run without drilling.

Back to Back Channel: 41×82mm

When a single channel isn't strong enough, two channels are welded back to back to form a 41×82mm section. This dramatically increases the load-bearing capacity and rigidity compared to a single 41×41.

Best for:

• Long unsupported spans
• Heavy mechanical equipment
• Primary structural support frames
• Situations where deflection under load needs to be minimised

Direct Cutting stocks 41×82mm back to back channel in plain and slotted, in 3m and 6m lengths, all at 2.5mm wall thickness.

Finishes: Pre-Galvanised, Hot Dipped, and Powder Coated

For versatile applications, it is crucial to assess the strut channel sizes you require. Different industries might have specific needs when it comes to strut channel sizes, so assess your project carefully.

As you explore your options, keep in mind the various strut channel sizes that can accommodate your installation needs.

Pre-galvanised is the standard finish, a zinc coating applied before forming, suitable for most internal applications. All standard stock at Direct Cutting is pre-galvanised.

Hot dipped galvanised is applied after forming, giving a thicker, more robust zinc coating. Specified for external installations, coastal environments, or anywhere the channel may be exposed to moisture over a long period. Available on 41×41 2.5mm slotted channel.

When evaluating back to back options, also consider how the strut channel sizes will affect load-bearing capacity and installation ease. The choice in strut channel sizes can greatly influence your project's success.

Powder coated is available for applications where colour matters, plant rooms, data centres, or anywhere RAL colour coding is used. Direct Cutting offers powder coated strut channel cut to any size.

3m or 6m Lengths?

Both are standard stock. The choice usually comes down to:

• 3m lengths - easier to transport in a van, less waste on shorter runs, lower cost per order
• 6m lengths - fewer joints on long runs, lower cost per metre, better for large frames

In conclusion, when planning your project, carefully consider the strut channel sizes to ensure you achieve the best results.

If your run length doesn't divide neatly into 3m or 6m, Direct Cutting offers a pre-cut channel service you specify the exact length you need and it arrives ready to install. No cutting on site, no wastage, no minimum order.

Quick Reference: Which Profile for Which Job?

Ultimately, the selection of strut channel sizes should be guided by the specific requirements of each project, ensuring optimal performance and safety.

Order Online, No Minimum

All profiles are available to order online at Direct Cutting with no minimum order quantity. Whether you need a single 3m length or a full van load, pricing is the same.

Browse the full range at directcutting.com/strut-channel, or get your lengths cut to size at directcutting.com/pre-cut-lengths.

Not sure which profile is right for your job? Call the team on 0121 296 6307 - Mon-Thu, 9:30am – 1:30pm.

Finding the right strut channel sizes can save you time and money, making it an essential part of your planning process.