Cantilever arm chart
What a cantilever arm carries, what the post under it carries, and which of the two runs out first. Light duty ratings are published below; heavy duty and galvanised are rated per configuration.
How cantilever capacity works
Three separate limits apply to every cantilever run, and the lowest of them is your answer. Working to the arm rating alone is the mistake that puts loads on the floor.
The arm
An arm’s rating falls as it gets longer, because the load sits further out from the column. A 1200 mm arm carries roughly half what a 600 mm arm of the same section carries. Arms are rated for a load spread along them, not concentrated at the tip.
The post
The post rating is for the whole column and every arm on it shares it. Four arms at their individual limit will usually exceed the post, which is why the post figure is the one to size a run against.
The base and the floor
A cantilever column is trying to tip over, so the base length and the floor anchors are doing real work. A rating assumes the base supplied with the system, anchored into a slab that can take it.
Light duty arm chart
Single sided runs. The per-post figure is the total for the column, not per arm.
| Arm length | Load per arm | Load per post | Arms before the post governs |
|---|---|---|---|
| 600 mm | 500 kg | 1500 kg | 3 |
| 900 mm | 350 kg | 1200 kg | 3 |
| 1200 mm | 250 kg | 900 kg | 3 |
Double sided runs on 600 mm arms carry 500 kg per arm, 1500 kg per side and 3000 kg per post. Load both sides as evenly as you can — a double sided column loaded on one side only is a single sided column with the wrong base under it.
The figures are the same at 2400 mm and 3000 mm post heights. Height changes how much of the post rating a given load uses, not what the arm carries.
Heavy duty and galvanised
Heavy duty arms come in 900 mm, 1200 mm and 1500 mm, in a 100 × 120 mm section, powder coated or hot dip galvanised for outdoor runs. Posts run to 5940 mm, single or double sided, in two and three bay systems with 900, 1200, 1500 or 1800 mm arm centres.
Ratings for the heavy duty and galvanised systems are confirmed on the quotation rather than published here. They depend on post height, arm centres, bracing and how many arms are loaded at once, and we are re-checking the published figures with the manufacturer before they go in a chart. Ask and we will give you the number for the configuration you are actually building.
What cantilever racking is for
Long loads
Timber, steel lengths, pipe, conduit, extrusion, plasterboard. Anything that will not sit on a pallet and does not want an upright in the middle of it.
Clear front access
There is no front column, so a load can be picked anywhere along the run. That is the whole point of the system and the reason it costs more per tonne than pallet racking.
Outdoor storage
Hot dip galvanised posts and arms are the version that goes in a yard. Powder coat is for indoors; it will not last outside on the coast.
Mixed lengths
Arm centres set what you can store. Close centres suit short heavy lengths; wide centres suit long light ones. Get this wrong and half the run is unusable.
What to tell us for a quote
- The heaviest single load and how long it is.
- How much you need to store, in tonnes or in metres of run.
- Indoors or outdoors, which decides the finish.
- How you will load it — forklift, crane or by hand — and from which side.
- Your ceiling height and floor, which decide how tall the posts can be.
Cantilever racking is covered by the same standard as pallet racking: load signs, configuration drawings, annual inspection and the rest. The AS 4084 compliance guide sets out what comes with an installation and what you have to do with it afterwards.