We have a lovely jumping pen, that is oblong in shape. The footing is a carpet sand mix, and is lovely on the sides, but at the ends, where the horses have to dig in a bit to turn, they are punching through to the base. It gets very deep and somewhat slippery, any suggestion on firming up the ends without taking all the footing out and re-doing it?
"You can't really debate with someone who has a prescient invisible friend"
I am a bit confused. How can it be both deep and have them punching through to the base at the same time? Are they going right through the deep footing to the base? If so, perhaps the issue is that you have to take some (not all) out and replace with something to add stability?
If the base has developed ruts or holes then, yes, I think the ultimate solution is to start over. However, if it hasn't gotten that far yet, maybe it is still fixable.
No you have the same problem I have in my rectangular round pen and I have good base then stone dust well rolled packed wetted and solid been down for years and some sand on top. We also have it slightly cambered to get good drainage and sun hits it all winter..The problem we found is like you the make the turns and dig it up. We had a very wet winter and it got soaked thru the base. Now that its sunny and dry I am having stone dust leveled re rolled and sealed base best I can do..
I was guessing the same as jbrp. When they are free jumping/lunging they just get going faster and tear down to the base. I am actually making an area specifically for lunging/free jumping because when I lunge in my ring the same thing happens. I often get horses in from the track that have toe grabs on and it does a lovely job of getting down to the base in my ring even though the base is like concrete!
I also suggest bringing some of the footing off and trying to tighten up the base. Maybe your sand is wrong and not compacting enough?
I think I would pull back the footing in those areas and see what is going on with base. If the base got soft and they were punching thru to the base you may need to fix the base.
As for the deep shifting part...wish I had some advice for you. I built an indoor last year with sand footing and I am having the same issues. I asked for 3 inches and in some areas it is much deeper. It is tolerable if I keep it really really well watered but as soon as it starts to dry the footing lacks stability. I am trying to decide how to fix it. Taking some out and adding something like felt was one of my thoughts but you say you have carpet. Maybe the carpet has broken down to the point that is no longer adding stability? Perhaps the original owner added the carpet to add stability to the sand and the solution is to take out some of the footing add something that will add stability?