Dreamed of having your own all-weather arena? There are several options for their construction, but taking shortcuts is a risky business, writes Neil Clarkson.
What’s the best way to build a horse arena?
If you’ve found someone who knows, why not ask them to explain the true meaning of life while they’re at it.
Building an arena is as much art as it is science. If you asked a dozen people for their views on the best way to build and surface an arena, you will end up with a dozen different answers.
If you get sick of asking, why not do some online research? Your eyes will end up as rectangular as your arena, and you’ll still have no definitive answer.
The problem is regional variation. The raw ingredients for any arena – be they clay, shingle, sand, or limestone – vary from district to district. Lime from one quarry that performs superbly in one arena construction may have different qualities to that taken from a quarry 30km down the road.
There are huge variations in the kinds of sands you can buy. Clays, also, demonstrate many different properties.
Ignore the following areas at your peril:
Pools of water create soft spots. Aside from affecting ride quality, they will also ultimately lead to failure of the surface and its sub-layers. You will eventually end up with patches containing a porridge of all the layers you had lovingly (and expensively) trucked in and used on your arena.
The one thing you don’t want is water pooling on your arena.
There are two critical issues for drainage. Firstly, you want to create a gentle fall so that water is encouraged off the arena. The most common approach is to create a modest crown down the centre line, and have drains running along each side to collect the water and carry it away.
Rainfall will run through the soft top surface to the compacted layer beneath. From here most of it should run off to the sides. It’s simple in theory. Much will depend upon on your rainfall, the soil type, and, hopefully, using the natural lie of the surrounding land to make this all work.
If drainage is a major issue, you may need to depart from the model described above. A series of herringbone drains can be installed across an arena to carry water to the outsides.
However, these drains will need to be placed in a sublayer that remains reasonably porous when compacted. The whole drainage system will add considerably to the final cost, but may be the only solution if your only available area has a heavy soil and cops a lot of rainfall.
Geotextiles may be used to cover these drains to prevent other materials used in the arena’s construction entering the drainage system. This will naturally increase the final cost, but will greatly extend the life of the drains. Inadequately protected drains will quickly clog and fail.
At the other end of the arena-building spectrum, people have built successful arenas quite cheaply on bony, old free-draining riverflats.
If you can select high ground, you’ve got half the battle won. Normally, side drains will suffice. Seek advice if you’re unsure.
Finally, you may like to call it an all-weather arena, but show it some kindness. Using it straight after a 50mm downpour only increases the risk of damaging the crucial sublayers.
Most arenas have some form of edging. Be careful this does not interfere with the drainage of the arena, or all your hard work will be for nought. The last thing you want is water pooling around the outside of the arena because of edging that creates a barrier, as this is arena area that will normally get the most use.
Don’t skimp on the base materials
Even a modest 40m by 20m arena requires industrial quantities of material and it’s very easy to think that saving a few hundred dollars on the base materials won’t do any harm.
Let’s looks at a basic arena recipe: Excavate to a good clay base. (Bring in the clay if necessary). Apply at least a 100mm layer of AP65 (this is a natural mix of gravel and sand from which stones bigger than 65mm across have been removed). Once compacted, apply a similar amount of lime and compact it. Apply a thin layer of crusher dust and then your top layer to the desired thickness.
With AP65 weighing about two tonnes per cubic metre, you won’t get any more than 12 cubic metres per truckload.
For a minimum 100mm thick layer, you’ll need 80 cubic metres, or nearly seven truckloads, to cover your arena.
You’re better off when it comes to transporting in the lighter lime, with trucks probably able to carry about 20 cubic metres, but that’s still at least four truckloads.
Suppliers may be looking to charge you $15 a cubic metre or more to deliver it. If you’re reasonably close to the source, you might save on transport costs by hiring trucks on an hourly rate to deliver the materials. Be sure of your maths before committing either way.
Do not shortchange your arena on base materials. By doing so you’re reducing its ability to compact to a uniform hard layer that will prevent undesirable material from underneath coming to the surface.
Make no mistake. If your base layers fail, your arena fails. It hurts to throw money at something no-one will ultimately see, but those sublayers are crucial.
You can save some money if you have a suitable location on your property for any topsoil removed during construction. Otherwise, this material will need to be trucked away, creating additional cost.
Whatever use you put this material to, ensure that you regrass it as quickly as possible to prevent a muddy slurry running off during heavy rain and causing havoc, particularly when it comes to waterways.
Check before that top layer goes on
Arena construction has been compared to road construction. A road will only be successful if the tarseal or asphalt is going on to a hard, compacted base.
Exactly the same applies to an arena. It’s that top layer where you’re going to give your horse the grip and cushioning that will make the arena enjoyable for all to use.
Beneath that, you want a hard surface. If a horse’s hoof does chop through your top layer, you don’t want it damaging the layer beneath.
This will eventually lead to the two layers mixing and, ultimately, failure.
If you can easily dig up this layer with your heel, it’s probably not hard enough.
- Do your homework. Check out local arenas that have given good service and find out how they were built.
- Avoid low-lying areas, and pick a spot where any fall will help to carry water away.
- Excavate to a good base before trucking in materials.
- Don’t skimp on base layers. There are no shortcuts.
- Ignore drainage and there’s a good chance your arena will fail.
- Plan the project for the drier months. There will be plenty of trucks coming and going. You don’t want them stuck in your sodden paddock.
- Allow for regional variations in materials. A recipe that worked in one district may not work in yours.
- Keep up arena maintenance, and don’t use it after heavy rain until at least some of the water has drained off.
Get that top layer right
Before looking at the different kinds of arena surface materials, you’ve got to consider what you want to achieve with your top layer. Some people prefer a soft arena, others a much firmer surface. Unfortunately, horses can’t tell us which they prefer.
All of us want to avoid a hard surface that can cause jarring injuries.
However, there is little doubt that you can cause serious problems if your arena is too soft. You might think that you’re providing a lovely, easy-going surface, but there’s a real chance you’ll place undue stress on a horse’s tendons and leg muscles. Why?
An ideal surface will provide good traction and, just as importantly, an even, consistent base. This is because every animal, be it a horse, a human, or a hare, makes a split-second decision with every stride.
The brain decides the instant each leg has found firm footing and the muscles start to propel the animal forward. If the animal is in very soft sand, it’s very difficult to determine when the body should begin each “power stroke”. The result can be overstretched tendons and muscles. All will become clear if you go to a beach and take a run across a soft sand dune.
The top layer has to display a couple of other practical properties. You don’t want it to whip up a dust storm in a strong wind, and you certainly don’t want it taking flight in a gale. The best arena surface in the world would be little use in Canterbury if it cannot hold its ground against a hot, dry nor’west gale.
So what makes an ideal arena surface?
Cost, availability, and regional variation will all play an important factor in your final choice. In parts of the United States, for example, people have access to shredded leather.
In New Zealand, your key choices will probably be found among the following:
These create a good-value surface and provide some cushioning, but it will break down over time. It’s probably a better option in a drier climate. Wood chips or post peelings will last much longer than bark, which is usually too soft and will break down with use to a powder, only to blow away. It’s important the pieces you get are of reasonably uniform size to ensure your arena provides consistent footing. This surface will need an occasional top-up, so make sure you build your arena to allow continued truck access.
Old tyres are a real headache for communities to dispose of, as they tend to rise to the surface in landfills unless cut up. But processing plants are at least $2 million each, so we’re unlikely to see them popping up in any numbers around the country anytime soon. Internationally, rubber is considered an excellent surface and is sometimes mixed with sand. It needs to be free of the metal from steel-belted radials and the pieces should be of a reasonably uniform size.
River sand is a common finishing material for arenas. It can be mixed with sawdust or rubber to improve its properties. Not all sands are created equal, with considerable regional variation.
Sand is essentially broken-down rock, so it will not decompose like bark or woodchips. However, it will erode over time. That said, you should expect several years of good use before any major reworking needs to be considered.
The sand you choose will need to be “cleaned” – that is, all the silt and clay washed from it. Using a sand with silt and clay will not only create a dust problem, but will lead over time to your arena surfacing compacting down.
Do not underestimate the dust issue. Breathing dust of any kind is a health hazard. The dust from silica sand, for example, is known to cause a nasty lung condition called silicosis. Aside from the health concerns, it will cover surrounding buildings and features, and could easily get you in trouble with a neighbour.
The sand should also be screened. This is where undesirably large particles are filtered out to leave material of uniform size. Ideally, you want a mix of round and angular particles. If there are too many round particles, the sand will move too easily under your horse’s hooves – kind of like running on marbles. Sharper particles aid traction, but if your sand is all sharp material, it may prove to be too abrasive on your horse’s feet.
Essentially, the more uniform the particle size, the less prone the material will be to compaction. Compaction is simply a fancy term for smaller particles filling the gaps between bigger particles. Some regions have an abundance of braided rivers carrying countless tonnes of river sand. Other areas, particularly those with a recent volcanic past, may tend to produce sands containing softer volcanic elements, such as pumice. Some of these materials will break down with use, turn to dust, and blow away.
When it comes to sand, you’ll need to talk to the companies that process it, who should be well aware of which of their products have been used with success on horse arenas.
Better still, ask people who have built an arena what they think of their sand surface.
How thick should the top layer be? As a general rule, start at no more than 50mm and, if you’re not satisfied, add 10mm or so at a time until you’re happy.
Limestone/granite chips, or similar
It’s possible you may have access in your region to an affordable chip. Some, limestone in particular, will break down with use and will need replacing. If you feel this will make an adequate surface, ensure the material you take delivery of is of uniform size. This will ensure a consistent riding surface and reduce the amount of compaction. Could it be mixed with a coarse local sand to improve its qualities?
Wouldn’t it be great if soil provided an ideal arena footing?
Unfortunately, most top-soils display many unsuitable properties. It tends to become compacted, can be slippery when wet, varies greatly in its properties between wet or dry, and can become dangerously uneven when it chops up then dries out between uses.
Drainage is rarely good enough to function effectively. That isn’t to say that, with the right soil type and the correct amount of moisture, top-soil won’t work well. However, maintaining conditions that are “just right” for any length of time will usually prove nigh-on impossible.
Neglecting maintenance will shorten your arena’s life. High traffic areas will tend to compact down, or the topping material will be flicked to one side. Ignore it for too long and you’ll find your horses working on the compacted sublayer.
Traffic wear is easily dealt with when tackled early, with a light harrow-like device that will not only redistribute the material, but penetrates a little, helping to loosen any compaction.
Given the gradient placed on an arena, the tendency is for the sand or other surface material to slowly but surely migrate to the outside.
If you ignore this tendency for too long, your only option will be to get a small excavator with a split bucket to gently scrap it back towards the crown.
My personal choice for dragging an arena is a heavy metal bar with two loops of chain trailing behind, towed behind a quad bike. During any dragging session, I always go in one direction only and offset the bar a little so it tends to push the material back uphill. This may not totally remove the eventualy need for a small excavator, but it will certainly delay it.
Do your homework
Don’t expect your arena to come cheaply. There are no cunning or cost-saving shortcuts to success.
Your investment will be similar, and probably more, than getting out your chequebook for a new horsefloat.
You’ll be doing well to find a contractor who can build one for under $12,000, but much will depend upon how close the raw materials are. For the likes of your base fill, you’ll most likely be paying more for cartage than for the material itself. You can easily pay $20,000 for a finished arena, so it’s important to get everything right.
There are contractors who specialize in arena construction. They will know the best local materials to use and their all-important properties.
However you decide to proceed, talk to locals who have built an arena. Ask to visit and question them on any problems they may have encountered before or after it went into service.
Many successful arena surfaces have evolved over the years. It may have started with a sand topping and ended up with a woodchip/sand mix. Ask the owners why they modified their layer of footing.
These kinds of insights will ultimately prove invaluable in building a successful arena; and those that have given good service for many years should be given particular scrutiny.
The last thing you want to do is build an arena that fails, because one thing is certain: you’ll be hearing the rumble of heavy machinery again – and getting it fixed won’t be cheap.
First published on Horsetalk on September 20, 2006