Things You'll Need
Flat rocks 2-inches high
Automatic concrete mixer
Masonry wood float
Even the smallest of fountains can weigh hundreds of pounds. Add in the weight of water and you'll find that a fountain requires a solid cement base to provide a strong stable foundation. Creating a slab of cement is a fairly simple process, but it will require some work on your part. Once completed though, it should provide you with the cement base you need to support even very heavy fountains without the fear of a slowly sinking piece of art.
Measure the base of the fountain and dig a foundation hole the size of your fountain plus 6 inches on all sides. The foundation hole should be 6-inches deep to allow for a gravel draining bed along with the concrete. Use a concrete calculator to determine the amount of concrete you'll need for your slab. You can find a concrete calculator at the concretenetwork.com site (see resources).
Purchase enough materials to create your steel reinforced concrete slab. You can buy the materials at a home improvement store and rent the tools necessary from an equipment rental shop. Make sure to get enough concrete to complete the job at once, as taking a break during the pouring of the slab can lead to a badly bound base.
Sink a form for your slab into the foundation hole along the edges. The form can be made from wood, hard plastic or rubber, and is placed so that the materials used for your slab will not overflow the space.
Take the gravel and create a 2-inch layer with it in the bottom of the hole. Level the layer out, packing it firmly, using the spade.
Place a flat rock on the gravel bed every 3 feet to serve as a level for holding the rebar (steel reinforcing bars).
Make a grid using the rebar, on top of the flat rocks placed on the gravel bed. Rebar helps to reinforce your concrete slab, giving it the strength necessary for the weighty fountain.
Mix the concrete in the wheelbarrow according to the manufacturer's instructions. Pour the mixed concrete into the hole on the gravel bed, filling the hole to the level of the forms you placed into the ground.
Use the float to level the surface and drag moisture to the top and then use the trowel to smooth the surface.
Cover the foundation slab with a piece of plastic. Remove the forms after 24 hours, allowing it to cure for a week.
After the concrete has cured completely, apply a sealer to protect it from the weather.
Use pre-mixed concrete as a shortcut to combining the cement with sand.
Cement can burn the skin so wear rubber gloves when working with the material.