Cantilever racking is the go-to system for storing long, bulky or awkward loads — timber, tube, steel sections, plasterboard, pipe, guttering and panel products — that simply will not sit on conventional pallet racking. Because it has no front uprights to get in the way, you load and pick along an open face with a forklift or by hand. This buying guide explains the components, how arms and load ratings work, and how to specify a system that is safe and fit for your stock.
The components of a cantilever rack
Every cantilever system is built from a few core parts:
Uprights (columns): the vertical members that set the overall height and the number of arm levels.
Bases: the horizontal feet that bolt to each upright and provide stability — base depth is what stops the rack tipping under load.
Arms: the horizontal cantilevered supports the load rests on. They are height-adjustable up the column and fitted with removable end stops to stop stock rolling off.
Bracing: the cross and horizontal braces that tie a run of uprights together into a rigid structure.
Straight (parallel) vs tapered arms
Arms come in two profiles. Parallel (straight) arms are the same depth along their length and suit heavy, evenly distributed loads. Tapered arms are deeper at the root and slimmer at the tip, which keeps the loading point closer to the column — useful for lighter or shorter loads. Our cantilever racking range includes both: GPC parallel-arm racking rated at 250kg per arm with arms adjustable in 150mm increments, and GPC tapered-arm racking rated at 200kg per arm, both fully welded with end stops.
Single-sided vs double-sided
A single-sided rack has arms on one face and is designed to stand against a wall. A double-sided rack has arms on both faces of a shared row of columns, doubling the storage in the same footprint and ideal for an aisle with access from both sides. Tapered-arm racks in our range come in both single- and double-sided configurations.
Starter and extension bays
Cantilever racking is bought as starter bays and extension bays. A starter bay is a complete standalone unit — for example a GPC starter bay with three uprights carrying 12 or 15 arms in 500mm or 1000mm lengths. An extension bay shares the last upright of the previous bay and adds more arms (for example four 1000mm arms on a single upright), so each run after the first is more cost-effective. Plan your total length first, then work out one starter plus the number of extensions you need.
How to specify load ratings correctly
Load capacity is quoted per arm, but three things govern the real working capacity:
1. Per-arm rating — the maximum weight one arm can carry when the load is evenly distributed along it (250kg per arm on our parallel-arm racking).
2. Per-column rating — the total of all the arms on one upright must not exceed what the column and base can safely carry.
3. Load distribution — a concentrated point load near the arm tip is far more demanding than the same weight spread along the arm; always load heavy items low and even.
For heavier or higher-density applications, the STOW Cantilever Racking System in our range is a modular heavy-duty option engineered to higher capacities. If in doubt, give us the weight and length of a typical load and the height you want to reach, and we’ll spec it.
Sizing and siting checklist
Load length & weight set arm length and per-arm rating. Arm reach should support the load without excessive overhang. Column height sets how many levels you get — leave clearance for the forklift mast or for safe manual lifting. Base depth drives stability; taller, heavier racks need deeper bases and floor fixing. Indoor or outdoor — galvanised finishes suit yards and external storage. Frames have wall and floor fixing points and should be bolted down; a forklift is normally needed to load the larger bays.
Safety and inspection
Cantilever racking is work equipment under PUWER 1998 and should be installed level, fixed down, and load-notice labelled. Like all racking it should be inspected regularly and given an annual expert inspection in line with SEMA / HSG76 good practice, with any damaged arms or columns taken out of use. Never exceed the per-arm or per-column rating.
Frequently asked questions
What is cantilever racking used for? Storing long or awkward loads — timber, tube, bar, pipe, sheet and panel materials — that don’t fit pallet racking.
How much weight can cantilever racking hold? It depends on arm and column rating. Our standard parallel-arm racking carries 250kg per arm; tapered arms 200kg per arm; heavy-duty modular systems carry considerably more.
Single or double sided? Single-sided against a wall; double-sided for free-standing aisles with access from both faces and the best use of floor space.
Does cantilever racking need fixing to the floor? Yes — frames have floor (and wall) fixing points and should be secured for stability before loading.
Still deciding which system suits your stock? Read cantilever vs pallet racking explained and our pallet racking buying guide. Browse the cantilever racking and full racking & shelving ranges.
This guide is general information. Racking layout and load ratings should be confirmed for your specific application and floor.