Saunas are believed to provide a number of potential health benefits. If nothing else, saunas provide a natural way to relax and remove some potentially unwanted water weight in a short period of time. Saunas can be built in a variety of ways. Flooring for a sauna does not necessarily have to be concrete, although it can be a desirable material for this purpose.
A concrete floor is one of the least expensive and easily maintained floors that you can use in a sauna. Concrete floors will be less susceptible to the moisture build-up that occurs and can be textured to avoid becoming slippery. Most saunas will maintain a fairly low temperature near the floor.
The type of material used for the sauna floor depends partly upon where you build the sauna. You likely won't need to pour a concrete floor if you're putting a sauna in your home. But you will have to consider ventilation and the sauna's effect on your home's flooring material. For outdoor saunas, a concrete floor is desirable mainly because of its durability. Install the floor so that it is slightly sloped to ensure proper drainage.
You can use any other material you wish for your sauna floor as long as it tolerates water. For instance, tile will work just fine and provide a more decorative look than concrete. Heavy duty vinyl and sealed cement can also be used. Wooden floors are not generally recommended because wood tends to absorb moisture and can harbor bacterial growth.
Regardless of the floor material you choose, you will need to guard against moisture buildup and potential bacterial growth. Use a water-resistant sealant that's appropriate for your floor. Sealants also make it easier to clean the floor.