Before I had mats, about every two years I added clay to the center of the stalls. I got a couple of neighbor boys and had a load of clay dumped. Just like TRR, we used a wheelbarrow and shovels. I didn't worry about too much tamping, the horses will do that for you. I tamped down moderatly but dodn't kill myself over it. I did have it mounded in the middle a bit, so when it was tamped down by the horse it was somewhat level. It was hard cleaning for the first week or so, but eventually it leveled out.