Many factors come into play in determining the perfect location and design for your new outdoor arena. The first consideration is how large and what shape of an arena do you want or need. The size and shape are mainly determined by the discipline of riding that you are involved with. A dressage arena is much different than a hunter / jumper arena. And, you may want additional room around the inside perimeter of the arena fencing to “walk” the horse in the case of a dressage arena. To help you begin the development and design process, here are some considerations to be made.
Consult with a professional who knows arena designs. Many “footing” (riding surface) suppliers can help with this design once they understand your riding needs. Determine the size of the arena and then go about finding just the right location. If possible, keep the arena fairly close to the stall barn, preferably near one of the barn exit doors. Most arenas we develop as part of a complete equestrian facility whether it be for private use or training are not farther than 100’ from the barn. Remember that grading can be very expensive so try to find the most level existing area you have. The arena placement as far as direction from the barn is not such a priority as the only real consideration is dust from the prevailing wind and that can be controlled with irrigation. If your project is cost driven then the least amount of grading (cut / fill of material) will determine where the arena is best located.
Once you’ve located the arena and you know what size it needs to be to meet your needs then the actual site preparation can begin. Generally if you are going to disturb over an acre of land with the grading you will need to obtain a land disturbance permit. Be sure to know if the immediate area you are going to work has any active state waters or wetlands / flood plains that may have restrictions and setbacks / no-disturbance buffer zones. Again, it is best to work with a contractor that is familiar with the construction of outdoor arenas. One of the biggest problems with outdoor arenas is dealing with the storm water (rain water). Ponding and washing of the arena footing can create problems and the arena cannot be used when it’s that wet and may need footing repairs far too often.
Grading comes first. To determine if the site has good suitable compactable material under the surface topsoil it is best to take a few samplings. If you have good material to work with you are ready to start. Make sure the contractor or you if you are doing the work yourself call Utilities Protection and get the area marked and located for any possible underground utilities. You do not want to have a potential accident by hitting an unknown buried electrical or gas line.
Clear the area of any trees, shrubs, and debris. Strip off the topsoil and place nearby to use around the perimeter of the newly graded arena for grass replacement and any plantings you may want to install. Typically the arena site should be graded with a crown in the center to shed surface water off all sides of the arena. This crown is approximately a 1-1/2% slope from the center to the sides of the arena. Compact this existing base material to a consistent 95% compaction rate. You should not be able to push a steel rod of ½” in diameter by hand into the soil more than 1-1/2”. The concept is to have this “sub-base” material so hard that the water runs off and does not penetrate into it or pond on top of it. This entire graded area also should be larger both in width and length than the actual footprint of the arena itself by at least 5’. And, when finished the overall site itself should be above the surrounding areas by approx. 12” so no surface water will ever invade into the arena from the outside perimeter.
Once the site is completely graded and ready for stone you have the option to install a perimeter French Drain system around the inside of the fencing at the arena edge. This French Drain is designed to collect the surface water running to the sides of the arena from the center crown. This French Drain system usually consists of a perimeter trench approximately 12” wide x 24” deep and has a perforated plastic tile line laid in the bottom with the balance of the trench filled with #57 stone to act as a filter of sorts. It is critical not to use any stone with fine materials in it as those fines will plug up the tile line. The tile line is then trenched out of the perimeter of the arena to a low collecting area such as a swail. The top of the trench at finish grade level must be covered with a geo-fabric to not allow the footing sand to contaminate the stone filter and also plug the tile line up.
You are now ready to install the stone base. The stone base is the layer of compacted stone that is just below the actual riding footing. This base is for support for all traffic including equine and equipment so as to not allow ruts or holes to form that would create a riding hazard. The stone can be something that is readily available at a local quarry and will compact to the 95% rate. Again, this is critical as you don’t want to be repairing the base in the future by having to first remove the footing itself. This stone base generally is at least 4” deep and sometimes up to 12” deep depending on the conditions of the compacted sub-base material. Most commonly 6” to 8” is best.
Now that the arena site is completely graded, drainage is good, and you have a good compacted stone base it is now ready for a perimeter fence. There are many choices for fencing and they range from and assortment of wood to wire, vinyl or even electric strand. It depends greatly on your preferences, needs, and budget, and if you are trying to match an existing style so take time to talk to an expert so you can make the right decision. Most commonly for outdoor arenas we see wood pressure treated 4” x 6” posts set approx. 8’ on center with 1” x 6” pressure treated fence rails. Make sure all posts are set in concrete. If using a pressure treated wood fence construction method your fence should not be painted for a least 2 -3 months after installation and needs to be below 18% moisture content for the fence paint to adhere properly. One other item to note is that the actual fence is installed just outside the French Drain system and the fence has some type of perimeter bottom footing “retainer” to keep all material in the arena.
Choosing just the right footing material – It seems everywhere we go everyone has a different idea of what footing to use and while some like one style others will tell you that it should be something different. Most commonly we see an angular washed sand or masonry sand mixed with an additive material such as rubber, natural or synthetic fibers. Some mixes will even have a wax-type coating for inside arena applications only that do not need watering for dust control. To be the most effective, your riding arena’s surface should hold moisture content of 8 to 12% through the top 2 or 3 inches. It is best to consult with a professional footing supplier who will be able to give you the pros and cons for each blended mix.