We use galvanized steel in-ground swimming pool walls over everything else on the market. Steel walls have been used for pools for over 75 years and still are today. Steel walls won’t flex or crack like polymer walls or fiberglass pools will. When a steel-walled pool goes in the ground, you can be reassured that it’s there to stay. Steel in-ground swimming pools are anchored to the ground with a band of concrete around it called a collar. This ensures that the pool can’t shift or move. We back-fill against the walls with #57 gravel. The reason for this is that gravel won’t settle, creating voids under the concrete deck and also allows for drainage around the pool. We do not use sand for the pool floors. We install a solid mortar based floor that remains nice and smooth, which not only ensures a longer life for the liner, but makes cleaning the pool easier.