Maximize safety, soundness, and performance by solving your equine arena surface snafus.
By Diane Rice, The Horse: Your Guide To Equine Health Care
Keeping your arena footing in optimum condition for your climate, geography, and riding preferences can be a real bear. Just as Goldilocks had a range of too hot/too cold experiences while visiting the home of The Three Bears, you might be plagued with one or more common arena woes that prevent you from fully enjoying your riding experience—or worse, jeopardize your and/or your horse’s safety or soundness.
In addition to the health and safety concerns it poses, the expense of repairing an arena surface can be overwhelming and the job labor-intensive.
Your base, drainage, and footing needs depend on your location. While arenas in drier, sandy, or sandy loam areas might perform satisfactorily without needing a sophisticated drainage system, those in wetter areas with heavy clay will become unusable swamps if they’re not equipped with one or more methods to divert water. And where one footing material performs extremely well, another might be a poor choice.
By gaining a basic understanding of arena construction, materials, and their functions, you can make better decisions about correcting any problems you have with your arena. And if you don’t yet have an arena, familiarity with these basics can help you plan your future dream ring. Read on to learn how you can correct current or future problems and make your arena, as Goldilocks says, “just right!”
Arena Construction 101
Basically, your arena consists of a series of layers, each of which contributes to its ongoing condition and serviceability. From the bottom up, these layers are the:
Sub-base consists of level clay or compacted site subsoil. It sounds fairly straightforward, but Glynnie Walford, CEO of Martin Collins USA, an arena surfaces company in Midway, Kentucky, says that due to the variety of soils across geographic areas, her company gives generalized advice to a potential client, then recommends local subcontractors who are familiar with soil composition in the region the arena will be sited.
“A heavy clay—aka gumbo—can heave, or swell, when wet and contract when dry, which inhibits drainage and, in severe cases, can come up through the riding surface,” she says.
On the contrary, she says a client in East Tennessee is having to blast rock away from his site. “If you’re building an arena on heavy or rocky ground, the best money you’ll ever spend is on getting an engineer’s report, obtained by drilling bore holes to a sufficient depth to know what’s beneath that ground,” she says. “If there’s nowhere else to put your arena, at least you’ll know what you’re working with.”
Drains are constructed with a series of perforated PVC pipes surrounded by gravel, laid in trenches cut into the arena base. A needle-punched geotextile membrane tops the trenches to allow water to seep through, while keeping silt and sediment from blocking the drains. The number of drainage lines needed depends on your climate, the substrata, and the lay of the land.
“If you’re on heavy clay, you’ll need more drains run than a sandy or loamy type of subsoil that drains fairly well on its own,” Walford says. “We normally cut in drains every 30 feet across the ring, and they’ll run to a perimeter drain with outfalls (pipes draining onto an open area or, in the case of heavy clay, into a land drain which will take the surface water away from your arena) at the lowest point.”
Base This is a well-drained, level compacted layer of aggregate that is clean (without dust or “fines” that could cause the layer of rock to seal over time), hard (not susceptible to breaking down with frost), and 4 to 6 inches thick.
Retaining boards and fencing These define the arena’s perimeter, ensure the footing is encased, and provide an anchor for the next layer: the geotextile fabric.
Geotextile fabric membrane Attached to your retaining boards and rolled out with 6-inch overlaps, these fabric strips are heated to seal the edges, which will prevent them from working their way loose and up into the riding surface.
Road base In wetter climates, some people apply an additional layer of finer rock base designed to facilitate drainage. However, Walford says that in short order this finer material might, in fact, seal up and inhibit drainage or work loose and pop up in your arena surface.
Footing The footing itself should be loose, well-drained, and 2 to 4 inches deep (2 to 3 inches for dressage, 3 to 4 inches for jumping and other high-speed disciplines).
Depending on your budget, your climate and soil conditions, the materials available locally, and your personal preferences, you can use mainly native soil for your footing and irrigate and work the surface frequently to maintain it, or you can purchase a surface material that meets your needs for the activities you plan for your arena.
Surface materials include:
- Inorganic components such as sand, silt, and clay. The most widely used arena footing is sand, frequently combined with other materials for optimum consistency;
- Organic material such as wood chips or coarse sawdust or shredded leather;
- Coated products including wax-, polymer-, or petroleum-based surfaces; and
- Additives such as rubber and fibers, which can provide a consistent, low-maintenance footing over a relatively long period.
Because outdoor arenas are exposed to the elements, rainwater and snowmelt will necessitate using a heavier material (that won’t float away) than you might use indoors. Inside, installing footing that holds moisture longer, such as one with a higher clay content, will cut down on watering needs, as would adding salt or a wax, polymer, or oil coating to inorganic components.
“I tell folks that building an arena is like building a road, except the top layer is cushioned footing material rather than asphalt,” says Eileen Fabian, PhD, professor of agricultural engineering at Pennsylvania State University, in State College. “All the preparation for drainage, sub-base, and base ultimately determine the arena’s success or failure.”
In addition to careful arena construction, Fabian recommends constructing a 2- to 3-foot shoulder—just like on a highway—around the perimeter of outdoor arenas to protect the edge.
Now that we’re fluent in arena, let’s get down to some specific concerns and learn how to handle them.
Problem: Too Loose
Compaction occurs when small footing particles fill the spaces between larger particles, thus “solidifying” the particle matrix into a hardened surface.
Among other factors, particle shape contributes to compaction, or lack thereof. Angular materials, such as manufactured sand or stone dust, are much more prone to compaction than rounded materials. According to Penn State Extension Service, your “just-right” particle will be subangular: Its corners have been knocked off, forming a good but not-too-tight fit.
Translation: If your selected footing’s particle sizes are all relatively equal, your surface will be less prone to compact and will instead remain loose—perhaps too loose.
Too-loose footing can be unstable, especially for riding at high speeds and making quick turns. So, to achieve a more solid footing, especially for performance events such as jumping, cutting, and reining, you can add smaller and/or larger-sized particles to vary the sizes. When mixed sufficiently the particles will “marry,” and your mixture will eventually compact.
Note that sand particles are subject to wear over time, rounding their edges and contributing to loose footing. Thus, beach sand, with its naturally worn particle shape, is less desirable than more angular mined sand. Even still, the broken-off corners of worn angular sand become dust, or “fines,” that you’ll have to control through watering.
Know that if you live in an area where mined sand isn’t available, you’ll have to ship it in (which is expensive) or adapt the materials that are available locally.
Problem: Too Hard
Arena footing that’s too hard is at the opposite end of the spectrum—its particles are not standardized enough, so a compact matrix forms.
Again, as they’re ridden on over time, footing particles wear and slip between larger, more angular particles, resulting in compaction. This is why topsoil makes a poor arena footing, with its varied particle size and consistency.
Mixing wood particles with sand can add cushion and increase the footing’s moisture-holding capacity, but wood also wears and decomposes over time (that is, its particles become smaller), which can contribute to compaction.
Stone dust (aka blue stone, rock dust, limestone screenings, decomposed granite, white stone) is a finer grade of what’s called “road base” used in arena preparation. It drains well and provides good stability and can function well as footing if it’s worked and watered frequently. However, if not maintained, it will compact and become near-concrete-hard and very dusty. When adding stone dust as footing, Fabian recommends using a narrow range of grade (particle) sizes to prevent compacting.
“Stone dust mixed with rubber will provide a less compactable footing than stone dust alone, while keeping the high stability that stone dust offers for quick changes in direction and speeds, such as jump takeoffs and landing activity,” she says, adding that stone dust isn’t a material she recommends if horse owners can afford something more suitable. “It’s very cheap, but very dusty.”
Problem: Too Slick
In addition to particle size (and shape), an arena’s footing matrix—the variety of materials in its composition—can alter surface consistency. In particular, clay particles’ flat shape allows them to slide across each other, contributing to a slippery surface when wet. Clay and, likewise, silt are dustier than sand because their particles are super fine, so they become airborne easily. The dust requires more watering, which contributes to the slip factor—a vicious cycle.
Wood fibers (hardwoods larger than chips or sawdust) interlace, providing good traction when added to the footing matrix. However, says Fabian, wood products can be tricky to work with: They must be kept moist to maintain their adhesive properties. Fully dried all-wood footing can become slippery as the wood becomes more brittle, causing horses to lose their traction. And all-wood footing composed of pieces larger than 1 square inch can become slippery when overly wet, as well.
Remember the principles of compaction. Adding stone dust, ground rubber, or sand fills matrix voids in large-particle wood footing, improving traction for the horse. For overly wet conditions, improving drainage or cutting down on irrigation can reduce slipperiness.
Note: Walnut and black cherry wood products are toxic to horses, so buy wood fibers from a supplier who’s knowledgeable in equine arena footing.
Problem: Too Uneven
Hartford says uneven footing can have its roots in the base. “It could be that the base wasn’t level in the first place or that it moved or swelled due to high clay content and poor drainage,” she says. “If it’s a base problem, a professional will need to do some remedial work. However, it could be that the footing wasn’t installed to an even, compacted depth throughout, or that due to incorrect maintenance, the footing has moved from one area to another.”
She recommends checking footing depth periodically. “About every four months, take a long screwdriver that you’ve marked in inches and carefully push the tool into the compacted surface to reach the base, being careful not to penetrate the base,” she says. “Take readings at 10-foot intervals around the track, up the quarter line, centerline, and three-quarter line, together with some random depths. Record these so you’ll be able to see immediately if your surface is becoming uneven. You can then alter your maintenance procedure accordingly.”
Problem: Too Deep
At depths of more than 6 inches, sand—either alone or combined with other footing materials—can stress or injure horses’ tendons, ligaments, and other soft tissue structures. Fabian and her colleagues at Penn State University recommend starting with about 2 inches and adding more in ½-inch increments until you reach your desired depth.
If your arena is already built and too deep throughout, depending on the type of footing and overall depth, Hartford suggests rototilling fiber into the footing to build a “root structure” and stability.
Fabian notes that if it’s a surface that wasn’t installed too deep but now has some areas where the footing is loose and deeper, “check your irrigation system thoroughly for leaks or blockages that could be preventing your arena from getting sufficient moisture in those spots.
“The correct maintenance of any surface is critical,” she adds, even commercial equestrian arena footing mixed especially for your space. “A level and consistent footing is key to the well-being of your horse, and it should be regularly maintained according to the manufacturer’s instructions.”
Problem: Base Layer Popping Through
Hartford says if you can see base or stones coming up through the surface, the only way to fully investigate and confirm the nature of the problem is to remove the footing. “It could be that a heavy clay sub-base has heaved through, or a stone base has been ‘blinded off’ with a smaller stone that has worked its way up into the riding surface,” she says.
Problem: Too Wet
If your arena’s staying too wet, you might be able to remedy the problem by bolstering your system for carrying water away from your arena. Talk to a professional to determine your drainage options.
Problem: Too Bright
Ground-up rubber can darken an arena’s surface to reduce glare. Fabian suggests ensuring that any rubber mixed with your arena matrix is free of metal from steel-belted tires or other foreign materials. “Rubber can be added to a sand or stone dust footing at the rate of 1 to 2 pounds per square foot of arena, by spreading with a front end loader or your method of choice and then harrowing,” she says.
Problem: Stays Frozen
Again, ground rubber to the rescue. Its dark color absorbs light and, thus, heat, thawing the rest of the arena footing matrix more quickly as it does. Consequently, rubber might not be an ideal addition to your footing if you live in a hot climate.
Problem: Too Abrasive
Abrasion injuries can, at the least, cause excessive hoof wear and, at most, take a horse out of competition due to soft-tissue injuries. Abrasion can be an issue especially with the high-speed stops, spins, and turns of reining and cutting. If your horse has gotten abrasions from arena surfaces, you might want to consider softer footing materials such as wood products or shredded leather.
But abrasions are the tip of the iceberg when it comes to arena-related injuries. Carolyne Tranquille, BSc, who has studied surface-related injuries at the Animal Health Trust, in Newmarket, U.K., says contributing nonsurface factors might include the horse’s age, discipline, training regimes, and competition frequency.
“Based on the results of our investigations … arenas with deep, boggy, or uneven surfaces increase the risk of lameness, and arenas that are poorly maintained or have no base tend to have negative properties,” she says. “More frequent arena maintenance reduces the risk of lameness, and our recent work has shown that superficial harrowing and watering alters the properties of the surface and the movement pattern of the horse … making uniformity across the arena an important goal in surface management.”
Goldilocks might have had to test all the options before she found the perfect porridge temperature, but you can skip the experimentation and use the knowledge you’ve gained to evaluate and fix your arena’s faults, maintain it regularly, and keep it in “just right” condition.
Reprinted with permission from The Horse: Your Guide to Equine Health Care/TheHorse.com. Find more veterinarian-approved horse care information at TheHorse.com.