I have a doctors office that has a back door that is below ground level. It has a two foot brick wall that you step down into. The wall is even with the ground. I can't build it up higher because it would flood the heat pump next to it. My proposal was to come on the other side of the heat pump and put up a wall that channels the water away from the building. This does not have to be more than 7 or 8 inches tall and 6 feet long. The building is red brick. What stone would anyone suggest I use? Red castle or what?