As a new horse owner I decided to build a run-in with 2 - 12 x 12 stalls for our Thoroughbred (gelding) and Hackney (mare). At first we had a dirt floor which quickly became unmanageable with muck and mud. I then tried gravel dust about 4" thick. This was definitely a step up and worked well during the summer but we had a wet Winter and it seemed that we were back to ground zero wearing the rubber boots! I then purchased some used stall mats and placed them over some fresh gravel dust. Again this was a step up but when it got wet again the mats shifted and muck and mud oozed up between the mats and the mats soon disappeared.
I had had enough! So I got my Bobcat and pulled it all out and concreted the entire stall area including a 24" walkway in front of the stalls. I put about a 1/4" slope on the floor and power-washed the mats and replaced them over the concrete. What a difference! And the horses obviously agreed! I NO LONGER HAVE TO MUCK! The horses do all there business outside in the field! The most I do now is sweep a little uneaten hay from the stalls and I do mean little - they even kick out the bigger pieces themselves! I'm sure that you "old pros" will laugh at all this but hopefully it will help a novice! I learned the hard way!