Advice on new outdoor arena

[tysonvalleyfarm]

I am getting ready to build an outdoor arena on our farm. It’s not going to be huge - 80’ x 100’ - but I want to build it, of course, as best as possible while not spending an outrageous amount of money. I’m figuring I’ll spend upward towards $10k to get as decent an arena as possible that is usable year round.

I will start by saying I do have the Underfoot booklet, but I’d still like to get some opinions. The place where the arena will be drains fairly well and is already mostly flat. Some things I’ve read talk about loam being preferable to clay. But is it better if I have clay put down on top of the loam, then add my 6" base of stone dust? I’m concerned the loam is too soft and the stone dust will settle into it. Or will the loam work well on its own? I also plan on putting fabric down between layers to prevent them from mixing. Perhaps the fabric would eliminate the need for clay?

I also plan on having french drains put in along the sides of the arena. As long as the stone dust is packed down well, should I have channels cut in it to assist in draining? I’ve also seen many people say they had the stone dust put down and rode on it for a long time until it hardened. If I have him use a compactor, can we get good results without having to let it sit for a long time?

Lastly, I believe the best sand for me to use is C-33 concrete sand. We’ll be putting in 2" or 2.5". Have any of you had trouble with horses losing footing on this sand? Any good alternative sands just in case C-33 is too hard to come by? We will be doing jumping quite a lot, though only a couple horses a day. I’d like to avoid having to put some sort of additive in the sand if it’s not necessary to allow stable footing and impact absorption, but we will do it if we need to.

Any advice is greatly appreciated!

[Libby2563]

@tysonvalleyfarm

I also plan on having french drains put in along the sides of the arena. As long as the stone dust is packed down well, should I have channels cut in it to assist in draining? I’ve also seen many people say they had the stone dust put down and rode on it for a long time until it hardened. If I have him use a compactor, can we get good results without having to let it sit for a long time?

Sounds like you’ve done your homework! I can’t address very many of your questions but as to what I quoted above, I don’t think you need channels in the stonedust as long as the base is properly graded and the area you choose naturally drains well. My arena (standard dressage arena so about 66’x198’) is crowned with a 1% grade from centerline to the long sides. Others in the area have a 2% grade from one side to the other. Either can work. That is enough slope that it should drain well but not enough to be noticeable or cause footing run-off. My friend did need to put french drains in her base but that’s because it turned out there was a spring underneath one corner, which they discovered when that corner collapsed during construction. Otherwise I would say it’s probably not necessary and will add to your cost.

I also do not have french drains along the sides, just appropriate grading with a swale to channel water away from the arena. My ring drains terrifically well after heavy rain, just with proper grading and swales. Here are some construction pics of my ring, which was put into a not-at-all level area, if you’d like to see what I mean: http://thesmallhorsefarm.blogspot.com/2015/02/building-outdoor-riding-arena-with.html. Although actually you can see the swales a little better here: http://thesmallhorsefarm.blogspot.com/2015/03/mirrors-for-outdoor-riding-arena.html.

Also, I did not wait between the base and the footing. My contractor has done tons of arenas and does not find that necessary. He compacted it very well and also added water to help with the compaction. We had a dry few weeks so he actually had to bring in water trucks for that. Worth it though!

[tysonvalleyfarm]

Libby, thank you for your input! Watering the base to help compact it is a brilliant idea. I will definitely add that to the list of things I want to make sure we do to help compact the base. It would be great if we could just use swales instead of french drains… What type of sand did you use for your arena?

[Libby2563]

@tysonvalleyfarm

What type of sand did you use for your arena?

I actually got really lucky and was given an arenaful of sand and Lightfoot (rubber) footing that a local boarding stable had removed to replace with sand and GTG. It was only about a year old too! Unfortunately that means I don’t know exactly what kind of sand it is, sorry!

[tysonvalleyfarm]

No need to apologize! Thank you!! What an awesome opportunity to be able to get sand from another farm.

[mmeqcenter]

Personally I would not use clay as an arena base. Many people do but, I’m not a fan. It doesn’t drain, so must be sloped to allow water run-off. I prefer a (also sloped) base of a material that drains.

Using a compactor removes the need for letting it “sit” for several months. The purpose of letting is sit is so that it settles and compacts over time. If you’re compacting it mechanically with a roller or such, then you don’t need to let it sit.

I like concrete sand a lot for footing.

[tysonvalleyfarm]

Thank you for the input. So I just had my contractor out to discuss the project. Based on our somewhat soft soil, we are planning on putting a fabric down between the subbase and base. We will be doing a stone dust base, 6" compacted. He’s going to bring me samples of sands, but he said the other two arenas he’s seen built used masonry sand.

I’ve seen good and bad things about masonry sand. And that it can vary a lot from place to place. When I get the samples of sand, what am I looking for in terms of how it feels? I know I don’t want anything round…But how can I tell this based on feel?

Forgot to add that the guy who will be building the arena is very good and happens to be a good friend. I marked up the Underfoot booklet with some notes and basically assigned him pages to read!

[Showbizz]

I used concrete sand in the last outdoor I built. Now, there may be many types and shapes, but I do know mine rolled and was a bit unstable. I used it for 7 years, then called someone in to look at it. He said I needed an angular sand to reduce rolling and allow the footing to stabilize. I’m getting ready to build another , and will do just that.

[mmeqcenter]

Strange, maybe you got the wrong thing accidentally? Concrete sand is supposed to be an angular sand.

Some contractors really push masonry sand. It is also a fine footing, but more expensive. Concrete sand can compact more over time, you must make sure to use Washed concrete sand to remove the fines and reduce compaction. Sometimes washed is not available, so they suggest masonry.

[Showbizz]

Mine was definitely washed concrete sand.

[tangledweb]

I have no specific advice, but around here just the material costs you are talking about would cost about $10K. Rock and sand costs do vary a lot by region, but “towards $10K” may not be a realistic budget.

[MMavin]

My base is much simpler than your plan, but 2" of washed concrete sand (angular) is holding up well over it and is not too slippery.

[FoxChaser]

Ask your farrier for their opinion about what type of sand to use. My farrier said to stay away from angular masonry sand as my horse’s feet suck. He wanted him on river sand only. I just put in an arena and my advice is to get your estimate from your quarry as to how much footing you’ll need, but keep in mind that it may change a bit as your arena guy works with it. We ended up using more Class I than estimated and were trying to finish up on a Saturday when the quarry closed at noon. Unfortunately we went with their estimate for our river sand and now I have a bit too much! It would have been better to have spread it as we went along instead of ending up with too much footing on one end. Don’t round up with final footing, always round down. You can always add more, but can’t really take it out easily.