Full indoor shot of a large warehouse or cold storage facility. Metal racking systems, painted red, are arranged in tightly spaced, double rows. The racking system spans the entire image width, creating a long, narrow aisle down the center. Yellow plastic or rubber bumpers/protectors are attached to the concrete floor along the bases of all the metal racking columns. The image's focus is on the structural design and organization of the storage space, with a clear view of the metal framework and the defined aisle in the center. Industrial efficiency and robust storage capacity with AJ Products racking shelves

How to build and expand your warehouse racking system: A simple guide

Looking to install or extend your warehouse racking system? Whether you're setting up storage for the first time or upgrading your space to meet growing demand, understanding the building blocks of racking is key to creating a safe, scalable and efficient storage solution.

In this guide, we’ll explain the difference between basic and add-on units, how to build a racking run, and why modular shelving can help your business save space and money in the long term.

Plan your layout carefully

A multi-tiered metal shelving unit by AJ Products. racking shelving unit composed of vertical metal support beams, horizontal red metal beams connecting the supports, and wire mesh storage baskets or containers at several levels. Yellow plastic corner protectors are affixed to the base of the unit. The image is well-lit, and the background is pure white.

Before installing your racking, it’s essential to think through the layout of your space. Start by measuring the available floor area, ceiling height and any fixed features such as doors, windows, columns, or lighting that may affect the configuration. A good warehouse layout should balance maximum storage capacity with ease of access, so it’s important to leave sufficient aisle width - especially if you use forklifts or trolleys.

Don’t forget to plan for the future. Choosing a modular system and leaving room to expand means your racking can grow with your business. Even a simple sketch on grid paper or the use of an online planning tool can help you visualise the layout. We can provide planning supporte advice if you’re unsure.

Not sure which racking is right for your space? Take a look at our Guide to the different types of shelving and racking to find the best fit for your needs.

What’s the difference between a basic and an add-on racking unit?

When you're setting up a shelving or racking system, the first thing to understand is that it's made up of different types of units. The two most common are basic units and add-on units. Knowing the difference between them will help you build your system in the most efficient (and cost-effective) way.

Basic unit: The starting point

Think of a basic unit as the first full section of shelving in your setup. It comes with everything you need for that section to stand up on its own

Two end frames (or four vertical posts , also called uprights)
A set of shelves or beams, depending on wheter you're storing items directly or using pallet racking
Cross bracing if needed, this adds extra stability to prevent wobbling

Add-on unit: The extension

An add-on unit, on the other hand, is designed to connect to a basic unit or to another add-on. It doesn't have both side frames, it only comes with one end frame (or two uprights), because it shares the other side with the unit next to it. This clever design lets you extend your racking run without buying a full set of parts each time. Add-on units slot in neatly, making your storage more cost-effective and saving space.

One end frame (or two uprights)
A set of shelves or beams
Cross bracing if needed

How do I build and extend my racking run?

In order to create a run of storage bays, you should start with one basic unit, which can then be extended using add-on units.

The basic unit is a complete stand-alone shelving bay. The add-on unit is designed to join onto the end frame of the previous bay (whether the basic unit or a previous add-on unit) and is not suitable for use without at least one basic unit within the run of bays.

Tip: Always ensure your racking is installed on a level surface and anchored properly to meet health and safety standards.

well-organized, industrial storage and distribution area with metal racking systems, with red supports and gray metal beams holding numerous carboard boxes and wooden pallets

a man working in a large warehouse. He is pulling a wooden pallet using a metal handle. The pallet is part of a system of metal racking and shelving storage.

Prepare the area for installation

The installation area needs to be properly prepared. Clear the space of packaging, debris, or old shelving to ensure there’s nothing that could get in the way. It’s vital to check that your floor is level and structurally sound - uneven or unstable flooring can lead to instability or long-term safety issues. Depending on the size and type of racking you’re installing, you may also need access to specific tools, a ladder, or even lifting equipment. Having all materials and components ready to go before you begin will make the process smoother and faster.

Follow manufacturer instructions exactly

Racking and shelving systems may appear simple, but they are engineered for specific loads and configurations. Always follow the assembly instructions provided by the manufacturer. Be cautious not to mix brands or substitute components unless they’re specifically designed to be compatible. Bolts, beams, and braces all play a role in structural integrity, so it’s essential to install them correctly. Fasten all fittings securely, but avoid overtightening, which could damage the parts or affect load-bearing capacity.

Anchor for safety and stability

One of the most overlooked, but critical, aspects of racking installation is proper anchoring. In most cases, especially for high or heavy-duty racking, floor anchoring is a legal and safety requirement. Anchors must be suited to your specific floor type, whether it’s concrete, slab, or another material. In some installations, additional measures such as wall ties or cross bracing may be needed to improve lateral stability. Anchoring not only helps prevent tipping or collapse but also protects against damage from forklift bumps or daily wear and tear.

Load the Racks Safely

Safe load distribution is key to maintaining structural integrity over time. As a general rule, heavier items should be stored on the lower levels, with lighter goods placed higher up. This helps to lower the centre of gravity and reduce the risk of tipping. Avoid overloading any one shelf, and ensure the total weight remains within the racking’s specified capacity - this information should be clearly stated in the manufacturer’s technical data. Spreading the weight evenly across the beams or shelves will also prevent bowing or distortion under pressure.

Carry out safety checks and signage

It’s also a good idea to fit load notices to each bay, indicating the maximum shelf and bay capacities - this is not only good practice, but a requirement under UK workplace safety guidelines. Ongoing safety is just as important, so be sure to schedule regular inspections to check for any damage, movement, or wear over time. Staff should be trained on how to use the racking safely, how to stack items securely, and how to report any concerns or impact damage promptly. A well-maintained racking system not only extends product lifespan but also reduces the risk of costly workplace accidents.

Further information

If you need any help with space planning, our customer service team is here to help. We can advise you on the most suitable racking or shelving type for your needs, put together a floor plan and even arrange a site visit if required.

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