Drainage is an important consideration in your arena.

There are a few ways you can keep costs down in your dressage arena and still have a decent place to school horses. We’re considering a standard 66- x 198-foot dressage arena, have six or fewer horses, and are not running a busy boarding or showing operation for horses, which would put much more wear on the ring.

Base First
The ideal arena has a base, a sub-base, and a surface. The sub-base is the ground underneath the topsoil that needs to be compacted for maximum density. The base, usually some kind of crushed stone or stone dust, goes next. Then, the surface footing goes on top of that. It’s best to have all three layers for optimum drainage and stability. But you can get by without a sub-base, which will save you some money. (People with clay soil may have more trouble trying to skip the sub-base, because clay doesn’t drain well, and the surface can get easily sodden.)

Identifying what kind of soil you have will dictate what materials you use to build your arena. Donna Foulk, a senior agricultural program coordinator at the Rutgers (N.J.) Cooperative Research and Extension, says that because regions vary so greatly, a local soil scientist is key to putting in a home arena. In New Jersey alone, for example, there is compact clay in the northern section of the state with topsoil near the middle and sand toward the coasts.

Other regions of the country allow for ever further variation. Beth Schwinn Greenbaum owns Renaissance Farm Sporthorses, Cypress, Texas. She put in an arena there and one in south Florida. In south Florida, what’s usually under the grass is what residents call "sugar sand, a deep, loose sand that could easily injure a horse’s suspensories. Locals stabilize sugar sand with a product called "sludge," a by-product of water treatment plants.

The Cost

With any project with so many variables—soil, price of contractor, grade of land, machinery rental—price ranges vary widely. For a 120' x 220' arena in Texas, which has a 4" base of compacted crushed limestone and 2"-3" of "concrete sand" footing, plus the labor and railroad ties, the cost was about $25,000. But in south Florida, the same size ring using sludge tilled into sugar sand for the base, plus 2"-3" of concrete screenings footing, railroad ties, lights and irrigation system ran around $15,000. If you’re starting with an area that needs very little grading, a $10,000 arena—without lights or a sub-base—is not out of the question. If you decide to wait on installing your own arena, see the April 2001 issue of Horse Journal for how to mow your own arena space in a pasture area. The July 2004 issue tells you how to set up a practice arena with cones and counting strides. To order "Under Foot," which has useful measurements for letter placement as well as other arena information, contact the USDF at www.usdf.org or 859-971-2277.

In Texas, Greenbaum faced "black gumbo," a sticky soil that also needs stabilization. There, she compacted the soil and put a base of crushed limestone, decomposed granite, and crushed concrete to a depth of about 4" to 6" inches before placing footing material over that.

Your regional Natural Resource Conservation Service staff can help you figure out what combination of materials will be most effective for your arena. Soils in the whole nation have been mapped, and somewhere a soil survey of your arena space is on file. Go to http://www.nrcs.usda.gov/ for a list of agencies by state.

Contractors
Finding a contractor to construct your arena is tough, since you want someone who is familiar enough with horses to comprehend what you want. But you want to avoid a "boutique arena designer" who could be expensive and might have more experience with jump design or decorating than with actual arena construction. Look for someone who understands pitch, drainage and soil composition and can obtain the proper equipment.

Your neighbors are your best resources for finding these professionals. Someone who has built a serviceable arena in your neighborhood will already understand many of the local challenges and available materials.

Slope
Whether the arena should be flat or sloped is one of your first concerns. A perfectly flat arena is, of course, ideal. But in areas with heavy rain or drainage problems, a sloped or crowned arena may be more effective and, in the long run, less expensive. A sloped arena has a slight incline—1 percent or so—so that water drains off. A crowned area peaks in the center so that water falls away. These slopes are invisible to the naked eye, but make a real difference in terms of drainage. A sloped arena can save on the cost of putting in drainage, as well. A construction company will use lasers to figure out the precise grade.

Drainage is the word. Any water that makes it under your arena will weaken its structure, so you want to keep the water moving around it. A French drain, placed around the arena’s uphill sides, is effective and often the least-expensive route. A French drain is piping placed within a sloped and rock-bottomed ditch and usually lined with a filter fabric. Topsoil goes back on top of the drain, and as rain seeps down through the layers of soil and fabric, it runs out the French drain, thereby avoiding your arena.

Put it to Use
• Find out what type of soil you’re dealing with. • A sub-base may be skipped, but not a base. • Sand is economical. • Adjust footing depth to your discipline.

Materials
Once you have settled the larger design issues, you can focus on your materials. Which material is locally available affects your base choices. Bluestone, for example, is a common base on the East Coast. But it’s not native to many Western areas and so would be prohibitively expensive. Texans use crushed limestone, crushed concrete, or decomposed granite for a base. Floridians till sludge into the native sugar sand, level it, let it cure for a month or more, and then put the footing on top. Whichever stonedust base material you choose to use, make sure the quarry knows that you want it all to be of one grade size so that it does not compact and harden too easily.

The base needs to be level--unless you are sloping or crowning your arena--and packed. It should be compact in order not to shift around under the footing. The base is also non-absorbent: You want excess rainwater to run off the sides of the surface and in to the drain, not trickle down to the base. Although jumping arenas need a base of anywhere from 7" to 12" because of how hard horses land on it, dressage arenas can get by with about 4" to 6".

Costs
Trying to keep costs down, Foulk put in an arena in New Jersey. She found a level spot and removed the topsoil. For a base, she used crushed bluestone from a quarry. To save on hiring a roller, she compacted the base with farm vehicles and riding. Now, however, she considers the riding a mistake, and blames the unrolled bluestone for some hock problems her mare suffered. (Another way to avoid paying for a roller is simply to let the base sit over the winter, and let it compact on its own through exposure to the elements.)

Sand is the most common--and often cheapest surface footing for an arena. "Cleaned and screened" sand is nice for arenas, because it is both less dusty and less likely to compact. But it’s also more expensive, so your best bet to keep costs down is to blend some rubber in with your lower-grade—also called "straight"—sand.

You will need to get rubber from a riding-arena footing company. (And don’t use rubber if you’ve got a latex allergy, because it will enter the air around the arena and cause a reaction.)

The U.S. Dressage Federation’s 2000 brochure on arena construction, "Under Foot," gives this useful sand calculation: arena length x arena width x desired depth of sand/324 = cubic yards of sand needed. For the tonnage of sand you’ll need, multiply this number by 1.3. You can always add more, but it’s hard and costly to have sand removed. Start with 1 1/2 inches, and go from there if you need more. Overly deep sand feels cushy for the first couple of steps, but it’s hard on your horse’s joints when he’s working.

Keep sand costs down by comparison shopping, and possibly hiring the delivery service used by the sandlot rather than having your contractor pick it up. Besides the obvious sand-and-gravel services, many nurseries, quarries, and landscaping companies sell sand.

Although not necessary, railroad ties or other barriers work to keep the arena demarcated and prevent your footing from spreading. Many horses respond better to some kind of perimeter fence, no matter how low.

You need to allow for drainage under the ties, or your arena will pond when it rains. Railroad ties can be staked with retaining bars—metal dowel-shaped bars that are drilled into the tie—so that the ties are not resting directly on the ground.

Bottom Line
You need a safe, flat spot to school your horse, but costs can be prohibitive when it comes to designer footing and fancy fencing. Stick with what’s available in your area, but don’t skip the base and be certain you have adequate slope for drainage. And give strong consideration to a perimeter.