Wacky arena construction question

[Simkie]

@endlessclimb

The hope would be it would prevent the mucky stuff you started with, which is presumably clay/silt that heaved it’s way to the surface.

Oh yeah, no, that’s not it. There is a base and it’s intact. The boggy is a breakdown of the sand/chip layer (which is all above the base.)

I’ve scraped down to the base, and removed the chip/sand mix. The edges have a clear demarcation between chip layer and sand layer.

I can replace the chips and cap with screenings or sand to replicate what I’ve got, or I can fill it all with screenings.

Replacing the chip layer, covering with geotex and capping with screenings is interesting but I worry about the geotex coming up and how that integrates with the layers I’m leaving. The geotex would only be a few inches deep.

[Amberley]

@Simkie

There are boggy areas. It appears the sand layer was breached in these, allowing the sand and wood chips to mix, and allowing water into the chip layer.

Your explanation is more clear now but your idea about what’s causing the boggy areas still doesn’t make sense. 3" of sand is not going to be “breached” in select areas and allow water below it. Water will drain through the sand everywhere. It’s sand. The fiber layer below was always designed to have water drain into it.

Your base is clay (I thought it might be stone dust that you were reading as sand). It should be compacted and crowned or slanted so the water drains off it. All the layers above it will be permeable. Perhaps the fiber is to hold water and reduce dust or to add spring but it’s part of the footing itself as far as I can tell.

Either your base has developed low spots where water is sitting which has broken down the fiber layer so it stays wet or it’s been cracked and water is coming up from underneath in those areas. Either way you’re going to have to scrape to the base. I don’t see another solution other than not riding when it’s wet.

[Simkie]

@Amberley

Your explanation is more clear now but your idea about what’s causing the boggy areas still doesn’t make sense.

I really don’t understand what’s not clear. There’s a sand cap on top of the chips in most of the arena. That functions fine.

The sand cap isn’t intact in the boggy areas of the arena, and has mixed with the chips. The chips are very deep. Because the chip layer is very deep.

Water sheets off most of the arena. It’s workable even after heavy rain. Because it doesn’t hold water. Horses don’t punch through the sand, even when it’s wet.

The areas where chips and sand have mixed hold water. And are very deep. Those areas are never workable.

I just need the arena to be workable.

[SusanO]

Yes it sounds to me that this was a DIY Fibar arena and then the wood chips became too slippery when wet and they added the sand to mix with the Fibar to resolve this problem. Back before textiles this was a thing in my area, but mostly using Fibar and not wood chips. BUT it got to be extremely slippery when wet if it was an outdoor arena and dusty when it broke down. So sand was added which did help abate some of the slippery. Properly mixed and at the right moisture levels it was a nice surface to ride on before it broke down too much.

And if the base was a DIY and not done properly I can see getting low spots in the base where water settles and those would hold wet sand and wood chips making the problem worse. Maybe you need to pull all the footing off and check out the base. Ka-ching!

[SusanO]

I am assuming this is outdoors and I don’t see how the sand would stay on the top of the wood chip layer after heavy rain. The sand particles are smaller and would filter down unless the wood chip layer is extremely compacted. Either way I think you have a problem with the base in the wet spots. What comes first - the chicken or the egg? Could the sand and wood mixing be because there is a hole in the base and water is pooling there and not that water is pooling there because the sand and fiber has mixed together?

[Simkie]

@SusanO

Yes it sounds to me that this was a DIY Fibar arena and then the wood chips became too slippery when wet and they added the sand to mix with the Fibar to resolve this problem

The sand and chips do not mix at all for the majority of the arena, and these areas function fine.

@SusanO

Either way I think you have a problem with the base in the wet spots

I HAVE dug out to the base in the largest boggy area, and it’s solid and intact.

[SusanO]

The wood would have to be pretty broken down and compacted for it to remain as a sub base under the sand. Unless you are in the desert and it doesn’t rain much OR it stays packed and undisturbed. Which means a horse’s hoof is not punching through the sand into the wood sub layer. But I would imagine if a horse gets a wild hair and takes off galloping around it could punch through the sand layer. And I am assuming the sand layer is what is absorbing the rain and water doesn’t get into the wood layer. But if a hole gets punched through the sand layer and the wood gets disturbed and churned up - now the rain does not run off because the wood layer is now absorbent and not compacted. And every time that hole gets rained on it gets softer. Think of water running to the place of least resistance.

I think having a wood sub base is prone to moisture and other weird problems in an outdoor arena but it was not your idea! Probably sounded like a good idea until it wasn’t. Maybe a quick fix might be to dig out the mixed footing in those areas and add a crushed rock base in those holes and compact it and the put footing on top of it. It won’t be easy and it might not work. Other suggestion is to scrape off all of the sand and wood chips and start over after you know the base is shedding water. Ka-ching! I just don’t know a quick fix.

[Simkie]

@SusanO

The wood would have to be pretty broken down and compacted for it to remain as a sub base under the sand.

It is not.

@SusanO

Unless you are in the desert and it doesn’t rain much OR it stays packed and undisturbed.

We’ve gotten over 7 inches of rain in May alone.

@SusanO

And I am assuming the sand layer is what is absorbing the rain and water doesn’t get into the wood layer.

As I’ve said a few times, water sheets off the top.

@SusanO

But if a hole gets punched through the sand layer and the wood gets disturbed and churned up

And as I’ve said, the previous owners turned out in this area and their horses dug through the sand cap, which was the beginning of these boggy areas. They’ve just grown as the edges fell in and mixed with the chip layer.

Yeah, scraping out all out and replacing will be spendy. The question is really how to make it workable.

…Actually the question was if this is an real method of constructing a riding surface, and it’s clear that it is not. Lol.

[SusanO]

Yeah - I am not a fan of using an arena for turnout or horses racing around in it. I think this idea sounded like a great concept but in practice it was a fail as you have found. Spot fixing might help but i think the best fix would be to strip to the base and start over with footing. I have no idea what that would cost but it probably will be $$$$.

[Simkie]

@SusanO

i think the best fix would be to strip to the base and start over with footing. I have no idea what that would cost but it probably will be $$$$.

10-15k in materials alone based on my back of the envelope math.

Which is not particularly tenable at this point in time.

But yes, I think we can all agree that would be the “best” fix.

[Amberley]

@Simkie

As I’ve said a few times, water sheets off the top.

I have many years of professional experience in this kind of work. Your “sand cap” is not a cap and it’s not watertight. Sand is porous- water goes through it. 3" of footing sand has not been magically keeping the fiber dry for years- it’s been going through it all this time.

You really need to get a professional in to give you some options. I imagine the fix will be to scrape the sand off, remove the wood chips and dispose of them, repair the base/ drainage and replace the sand.

[Simkie]

I’m just describing what I’m seeing I’m sorry that doesn’t jive with what you expect. This sure isn’t what I expected either.

Yes, I think we all know that the best way to fix this is to scrape it all off.

Thanks for confirming this isn’t an accepted way to build a riding surface. I’d certainly never heard of such a thing. But it’s actually worked well where the horses didn’t dig through the sand. So

[endlessclimb]

No way would I put the geotextile between the wood and sand layers. That for sure would get messed up.

Ok, new idea to try

Put the wood chips down. Compact them to the best of your ability. Then spray them with a heavy layer of that mulch glue stuff. Then sand.

[Grey623]

@endlessclimb

Then spray them with a heavy layer of that mulch glue stuff.

MULCH GLUE? I needed to know about this product years ago, thank you!

Grey

[endlessclimb]

It’s a thing! I’ve read it’s just wood glue cut with water but haven’t tried it “home made”. Great for areas that wash out.

https://a.co/d/7gz4YFs

[beowulf]

Simkie, I’ve seen a ton of open areas done this way in the NE- was this originally something else before a ring, like a yard or standing lot?

I used to work a construction company out here - many of them would clear the land, feed the cleared trees through a chipper, and then use the wood chips as filler and/or a base layer. Two reasons: one, contractors love cheap/free material – two, when you cleared a formerly heavily wooded area, it tended to flood. If the very bottom of what you’re seeing is clay, that may be the original substrate of the area once the topsoil was removed. NE has a lot of silty/loamy clay.

Using chips as a base or even top layer in areas with lots of moisture has been used here for decades. I’ve seen it drain really well in standing lots, though sometimes if it really rains, you have some floating chips and/or movement. My horsey-BFF has been doing it this way for decades with no issues, and we get a ton of rain here. Every 5 years or so she would go in and scrape off the woodchips and replace them; even then still cheaper than buying base material like stone dust and pea stone for her areas. Her paddocks have always been gorgeous.

If it were me, I’d just fill/replace with woodchips, compact down, and top with sand as the rest of the area is. I would try to remove as little as possible in the interim as to not disturb the remaining semi-behaved substrate. I wouldn’t be scraping off the whole thing either, unless y’all want to give me $15k or so to do it.

So much of my farm is McGuyver’d, strung together by baling twine or duct tape, shortcutted, and hillbilly-engineered. We do what we can, with the things we can afford.

I sympathize with your situation; scraping it all out wouldn’t be tenable for me either. Sometimes I wish I could sit every single owner of my property down in a room and ask them “WHY did you do that?!”. But then again, a hundred years from now I’m sure someone will ask that about me.

I just replaced one of the rotted out sills in my ~200+ year old house. I won’t shock the sensibilities of COTH by informing y’all how I did it.

[Simkie]

@endlessclimb

Then spray them with a heavy layer of that mulch glue stuff.

@endlessclimb

It’s a thing! I’ve read it’s just wood glue cut with water but haven’t tried it “home made”. Great for areas that wash out.

https://a.co/d/7gz4YFs

What is this black magic OMG. I like this idea a lot to help keep everything stable below as a new cap is added!

And WHOA @beowulf that you’ve actually seen/heard of this set up before! This was definitely built as an arena, and the base is definitely not native, but it’s nice to know that this sort of construction is a “thing” for something. Knowing the previous owners, they wouldn’t’ve brought in an arena person so not surprising if a different trade came in and said “well you know we could…”

@beowulf

Sometimes I wish I could sit every single owner of my property down in a room and ask them “WHY did you do that?!”. But then again, a hundred years from now I’m sure someone will ask that about me.

Oh god, so the same here

[endlessclimb]

It won’t last forever, but will buy you the time you need for mother nature to help you compact and settle!

[B-burg_Dressage]

I have zero advice, but do you have any pictures?

[NaturallyHappy]

Years ago, we had an awful ice storm and lost lots of trees. We mulched it up and made very nice walking paths to all the pastures. Wood chips don’t seem to hold moisture the way wood pellets do. Those paths lasted for years. I wonder if they put chips down and rolled/compacted them after they put down the base. If you choose to rebuild it, I wonder if you could rent one of those tamper things to do the area, depending on the size. If the rest of the arena is great, it might be worth trying to fix it first. And rain sheets off of mine, too. I would wonder how one drags this though, as to not get into the chips. OR maybe drag a small section to mix it and see what happens. Good luck- this sounds hard!!!