The nitty gritty technical details
Choosing a contractor
This can be daunting, but the best advice is to get as many bids and opinions as you can before you choose. An arena contractor is generally more expensive, but will have equipment perfectly matched for your project including the right size laser leveling graders that will save time; they should also guarantee their work if future problems arise. With that in mind, there is nothing wrong with choosing a road, or foundation-building contractor IF they understand the principles needed for horse arenas such as slope and compaction requirements. If you need to clear land, you may need two contractors, one to clear and one to build your surface. Make sure your bid includes removing all roots, rocks and organic matter down to your sub base. Anything left under your base will decompose and leave pockets, or may work its way up.
Permits
Your contractor usually will take care of permits as part of the bid if permits are needed. If you live in King County, you can determine whether you need a permit by visiting the Department of Development and Environmental Services web site.
In general, filling or excavation exceeding 100 cubic yards (approximately 10 dump truck loads) or creation of impervious surface over 2000 square feet requires a permit. If your situation does not require a permit, you still need to observe erosion control and sensitive area practices and protect adjacent properties.
Slope and Drainage
Generally, it is ideal to have a slope of 1% running from the center line of your arena to the sides. This gives the water (and your footing) the shortest amount of space to travel, while keeping the “slant” to a minimum for riding. However, if you are in a rain zone, built into a hill, etc., you may want to consider a slanted slope from one side to the other of 2%. The water has farther to run and may wash out footing occasionally, but your sub base and base has less chance of losing integrity from standing water. Once you clear your site, you can observe which way the water naturally travels. Then you can decide if and where you need drains and what type you will need. An experienced contractor can tell you this up front, but it is good to re-check and see what “really” happens after you clear. You don’t want to waste money on more drains than needed, but you also want to make sure you don’t send a stream of water onto your arena or your neighbor’s property!
Drainage can also be placed under your arena but is very expensive and needs to be engineered; the advantage is quicker runoff with the ability of a near flat surface area.
The Sub Base
Sub base simply means the dirt layer that remains once you have scraped off all organic matter and leveled your sight. Any soft spots in the sub base will be noticeable, therefore you or your contractor must level, fill in low spots and compact the sub base. If you want to make a perfect arena, you can have a soil engineer do a couple of tests to make sure your sub base will hold up. If you build your arena in the summer for instance, the soil will be dry and you cannot properly compact it without adding water. A soil engineer can determine this. Alternately, you can let your sub base sit for the rainy season; getting some compacting work done for free! Soil should be compacted to a density of over 90%. Even if you let your sub base sit, you should hire or rent a compactor (the bigger the machine the better) before you put down your base.
The Base
The base is put on your sub base or geotextile fabric, leveled to your chosen slope, rolled, compacted, rolled and compacted some more until it is like walking on concrete. Most contractors have their “favorite” material for doing this, but I would advise getting something you can live with if a horse manages to spook and bring up some material. For me, that means using a material 5/8" minus or less with fines that will “weave” together and compact tightly. The minimum depth should be 4" after compaction. For jumping, cutting, heavy or mixed riding use arenas, 6-12 inches of compacted base should be used.
The Surface
This is what you’ve spent all your time thinking about, right? There are so many factors in choosing a surface, you need to prioritize and decide what will work for you...and if you find that perfect surface, write us and tell us about it, please!
Most people recommend starting sand at 1 1/2 to 2 inches and adding more if needed. Hogfuel can be slightly thicker. You want your surface firm (but with bounce, traction and resilience) and not so soft that it is hard on your horse’s joints and tendons. It’s good to have your farrier and vet take a look at your final footing. Your biggest concern (beside your horse) will be the maintenance of your surface, so take into account what equipment you have to keep your surface level, moist and fun to ride on! There are additives you can apply to help keep the moisture level consistent, however you should do thorough research, including any possible health effects before you choose one. It’s easy to put them in, but not to take them out!
Ideas and enhancements for your new arena.
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Visual barriers are good. Arena #1 has a low dressage fence to keep riders on track. All barriers should be placed on top of your base. Arena #2 has 4" x 6" landscape timbers to contain the sand with 2' x 4' x 24" boards underneath every 8' for water flow. Inexpensive drain pipe was placed on top to define the arena and make it softer for a “crash” landing. Railroad ties are also often used for containment, rubber edging material can be put on the top to make them safer.
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A “Cool out track” is nice to have outside your barrier for warming up or cooling out in high use arenas. Both arenas pictured have these.
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Consider a horse-safe fencing for your arena, especially if you will use it for “free” work and turnout.
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Incorporate an observation area that is safely outside the fence.
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Consider planting shrubs or trees around your arena to mitigate dust, noise, pet traffic and make the area more attractive. This can also make a nice wildlife enhancement area for those helpful fly and mosquito-eating birds!
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Lastly, remember that organic matter is your arena’s enemy! Pick up horse manure, leaves, twigs and weeds so they don’t work their way into your base.
Arena #1 is Elk Run Stable, a schooling, boarding and dressage facility in North Bend, WA. The school horses work in the arena often, therefore, the main consideration for this owner was getting maximum cushion and resilience to protect the horse’s joints while providing good traction and an all weather surface. This is the perfect site drainage-wise—an important decision for this area of North Bend which gets up to 95 inches of rain a year! A good quality hog fuel was chosen because it provides the needed cushion and is heavy enough not to wash or blow away during big storms: hog fuel is easy to maintain and add to when needed.
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Arena #2 is a personal use arena. The main consideration was to be able to use it in any weather since there is no “indoor” option. Washed, screened granite sand was chosen to keep the dust down with a fairly large grain for good cushion and to keep washout at a minimum. Sand varies a lot from quarry to quarry so it’s good to get a sample, lay it on the ground for a while to see how it feels and holds up over time. Sand and/or wood dust can be irritating and once you bring in tons of material you are stuck with it! If at all possible, test your material out first so you don’t waste a lot of time and resources later having to keep it watered.
List of books and resources
Horsekeeping on a Small Acreage by Cherry Hill
General information about horse farm planning for a smaller property, including layout, building design, maintenance, etc. Probably the best single book for the small horse farm owner.
The Equine Arena Handbook: Developing a User Friendly Facility by Robert C. Malmgren and Deborah Helmers
Written from a soil scientist’s perspective, reading this book is a very good idea before construction starts, and it is extremely useful even after the arena is complete.
Under Foot by the USDF (United States Dressage Federation)
For questions regarding arena construction and maintenance, whether indoors or out, this small book contains more useful information than just about any other book that we have seen.
Helpful web sites:
You can also type in “arena footing” on your web browser and you can read about the growing number of recycled rubber products, their cost and best uses.
