Choosing arena footing: sand, shape, and what to ask your supplier.

Published 28 September 2026

Most footing problems are not depth problems. They are material problems, and they were decided at the quarry before anything was delivered.

Extension guidance states the goal plainly: footing should stay loose without compacting, while still providing enough stability to ride on. Those two demands pull against each other, and which material satisfies both depends on things most people never ask about.

The counterintuitive part

Here is the thing that catches people out, and it is worth getting straight before you talk to anyone:

What makes excellent base material makes terrible footing.

A base wants material that locks together and compacts into a solid, load-bearing slab. That means a wide spread of particle sizes, so the small ones fill the gaps between the large ones. Dense-graded aggregate does exactly this, which is why it is what goes underneath.

Footing wants the opposite. It should resist compaction and stay loose. That means particles of a relatively uniform size, with few fines to pack the gaps.

So when a supplier offers you a well-graded material because it “packs beautifully,” they are describing a virtue for the layer below and a defect for the layer above. Both come from the same yard. They are not interchangeable, and you order them separately — the base calculator and the footing calculator are separate for the same reason.

Particle shape decides how it rides

Sand grains come in shapes, and the shape governs the feel underfoot more than anything else.

• Rounded grains roll over one another. Think beach or river sand, tumbled smooth by water. It never firms up, so it rides deep and loose, and it works muscles and tendons hard.
• Angular grains have sharp edges that interlock. They give grip and stability, but taken too far they knit together and the surface goes hard.
• Sub-angular grains sit between the two, and this is generally the target: small shoulders that interlock enough for traction, with edges rounded enough to still allow slight movement and absorb concussion.

This is why washed river sand is so often a disappointment. It is clean, it is cheap, it is widely available, and its rounded grains are exactly wrong for a riding surface.

Fines: the thing that ruins arenas

“Fines” means the silt and clay fraction — the particles too small to see individually. A small amount helps bind the surface and hold moisture. Too much is the single most common cause of a miserable arena.

The reason is particle shape again, at a smaller scale. Clay particles are flat, and flat particles slide over one another when wet. That is what a slick arena actually is at the grain level.

So an arena heavy in fines gives you the worst of both seasons: slippery when wet, and a dust problem when dry, because those same light particles lift into the air. Riders get the dust, and so do the horses breathing it at head height.

Ask for the sieve analysis

This is the single most useful thing in this guide, and it costs nothing.

Any industrial mine or established sand producer can supply a sieve analysis — a breakdown of the material by particle size, largest to smallest. It tells you what you are actually buying instead of what the delivery ticket calls it.

What to look at:

• The spread of sizes. Tightly grouped resists compaction. A wide spread packs.
• The fines percentage — what passes the finest sieve. This is your slippery-and-dusty risk in one number.
• Whether it is washed. Washing removes fines. Sometimes that is what you want, sometimes it removes the little binding you needed.

A supplier who cannot produce a sieve analysis is selling you an unknown material for a surface that horses will work on at speed. That is a reasonable point at which to call someone else.

Additives, and whether they earn their cost

Once you have sand that behaves, additives adjust how it performs.

Synthetic fibre is the most common. It knits through the sand and holds it together, reducing displacement so the surface does not shear away under a hoof. It is what lets a blended footing be specified deeper than plain sand would sensibly go.

Rubber is added mainly for shock absorption. It has a practical advantage in cold climates too: a low freezing point, so the surface stays usable further into winter than plain sand will.

Wax coatings sit at the top end. They largely remove the watering problem by making the surface far less dependent on moisture, and they suppress dust. They are also expensive, and they change how the arena must be maintained.

One practical note the calculators reflect: additives are lighter than sand. A cubic yard of blended footing weighs less than a cubic yard of plain sand, which is why the footing calculator uses a lower density for blends and says so on screen. If you are ordering by weight, this matters.

The five-minute test before you buy

Get a sample. A bucket is enough.

1. Look at the grains in sunlight, ideally with a hand lens. Sharp and faceted, or smooth and rounded?
2. Wet a handful and squeeze it. If it holds a firm ball and feels slick, there are too many fines and clay. It should barely hold shape.
3. Let a handful dry and pour it out. A visible cloud is the dust you will be breathing in August.
4. Rub it between your fingers. Gritty is sand. Smooth and floury is silt.

None of this replaces a sieve analysis, but it will catch an obviously wrong material before a truck arrives.

Depth will not rescue the wrong material

It is tempting to treat depth as the adjustment for everything. It is not. Footing that is too deep is a genuine soundness risk — extension guidance is firm that sand deeper than 6 inches stresses tendons, and that most arenas should start around 2 inches and be adjusted from there.

If a surface rides badly, adding depth usually makes it worse. The fix is the material, the base beneath it, or the moisture — not another two inches.

Once you have settled on the material, the footing calculator will give you the tonnage, and it adjusts for plain sand versus a blend.

What to take to the supplier

A short list beats a long conversation:

• Can I see a sieve analysis for this material?
• What percentage is fines, and is it washed?
• Are the grains angular, sub-angular or rounded?
• Has this material gone into riding arenas locally, and can I see one?
• Is it sold by weight or by volume, and what weight per yard do you use?

That last question is worth asking every time. It is the number that turns a depth into an order, and assuming it is where most quantity mistakes begin.