I need to know the best material to use for drainage in a horse stall built on hardpan?

What you could do is what they do in Canada is this, use large pebbles as a first layer, then a

second layer of smaller pebbles, then a layer of gravel, then a layer of pea gravel, and the final layer of clay ( the sort they use on tennis courts) thats compressed to a smooth surface

that will then take care of the drainage for you. It is very effective drainage!

For your records, it has been noted that this type of flooring is to the beneficiation of the

horses hooves, that is to say it is better than concrete!

Please note that the layers should be not less than 2ins and not more than 4ins thick!!

The final top layer should be at least 4ins thick!

You need 6" of drainage rock to hold the fort, then 6" of pea gravel over that. You could contain it with railroad ties. I couldn't afford the pea gravel and went with crushed limestone that worked just as well. 4" deep, and it works like a bean bag chair in terms of comfort. Sand isn't good for feet, its congesting. Go with the gravel....around the water trough, gateways, run-in sheds, places that they loaf or you can fill a stall in the barn and spend time there. Really easy to clean...a 10-tined fork and treat it like kitty litter. Raking will give you a real Zen feeling, lol! Worked so well on developing the feet and fighting thrush, that I put it in the round pen and then dug out all the dirt in the barn and put it in there too. Never had any regrets. I eliminated the stalls and made the back half of the barn a big run-in and don't have to buy shavings anymore either. Funny though, the manure pile didn't get any smaller. Figures!

Hard pan does not absorb much moisture and it does not let any pass down thorough it. It would be great if you could have some one with a bucked scoop out a deep hole in the center and then fill it with rocks and gravel before you put the top on it so some of the wet will soak down deeper. Gravel base with sand or loamy dirt on top would help give you some drainiage.

Once the urine makes it to the hardpan it is going to sit on top and not drain causing a big ammonia smell. And all your drainage material will be coated in it adding to the aroma. I would not put draining material on top of this this but use the hard surface to your advantage. Either mat over the top, or if that is too expensive, just put your shavings and/or straw bedding on top. Just use more if not using the rubber mat or the hardpan is going to get gummy with urine. That way you can remove all the urine and uck with each stall cleaning.

We use rubber which Is good on concrete and on gravel because its soft and also if there is any excess water then you can just sweep it away.