If you are putting in an inground swimming pool, never use sand. If you are talking to an inground pool builder who only uses sand, politely say thanks and escort him out of your house. While using sand is easier, less expensive, and less messy, it is also product of being lazy, stuck in 1980, and not good for the end user. Simply put, you are working with someone who isn’t concerned with building the best swimming pool possible.
Strong Pool Krete is made up of Portland cement, vermiculite, and sand. When all three are combined and troweled out, you get a strong smooth surface for your liner to lay on. Pool Krete will setup and turn into a hard “cork board” for your liner.
When using sand under your vinyl liner is doesn’t hold its form as well as Vermic. The sand takes years to get fully packed down and not move anymore. HOWEVER, before it packs down you can feel waves and even make indentations with your heel in the sand. I am sure that you have been swimming in a pool when you felt there was a gap under your feet. That is from the substrate, sand, moving or creating divots.
A concrete pool floor is the best pool bottom you can get and the only way a top inground pool builder will build.
Above ground swimming pools are generally less expensive and more for the budget-minded consumer. Adding sand to the bottom is usually preferred as it is less expensive. Using vermic instead of sand is going to cost about $1,000 – $1,500 instead of the $300 for the sand, but if you want the best surface for your vinyl liner, then the option is well worth it.
Never use sand and vermiculite is an OK option; HOWEVER a concrete pool floor is the best surface available. The concrete pool bottom will hold it’s form and is structural so it will not more. An experienced inground pool builder will be able to pour a concrete pool floor faster and better than using vermiculite.
Learn all about concrete pool floor.
W226 N781 Eastmound Drive
Waukesha, WI 53186
3300 County Road 10
Minneapolis, MN 55429