A sauna is an inside room or free-standing building designed for either wet or dry heat sessions. In a wet sauna, occupants of the sauna throw water over hot rocks to create steam and humidity. In a dry sauna, the overall heat of the room is higher, but occupants don't throw water over the rocks. Both types of sauna are designed to cause occupants to perspire. Traditional sauna enthusiasts will leave the room after 10 or 15 minutes and rinse the perspiration off using very cold water, which also causes the pores expanded by the sauna's heat to contract.
You can build a sauna in an unused room or closet. Because of the moisture and water in a wet sauna, many wet saunas are built in basements. A dry sauna also could be built in a basement. Because of the water in a wet sauna, it is important that you seal the sauna from the rest of the house to prevent moisture problems outside of the sauna. Some people prefer a free-standing sauna and complete kits are readily available for outdoor free standing saunas. An outdoor sauna prevents any moisture problems in your house.
Woods used in sauna construction must be relatively soft to disperse heat and prevent discomfort or burns. Cedar is very popular due to its natural chemicals that inhibit mold and mildew. Nordic pine is popular in traditional Finnish saunas. A number of woods make good seats, including cedar, Nordic pine, Nordic white sprice and Abachi. Woods which are good, but not often used, include aspen, hemlock and redwood.
If your sauna will allow for an opening for a chimney, you have the option of using a wood fired sauna stove. An existing wood stove can be made into a sauna stove by making an iron or steel cage to hold rocks. The base of this cage should be larger than the wood stove and angled to funnel excess water away from the main stove to prevent rust.
Most people buy their sauna stoves. Aside from wood stoves, a number of gas and electric stoves are available. Electric stoves come in two types, traditional electric stoves that work using resistance heating and infrared stoves. Infrared stoves use less power than older resistance-heated stoves.
Regardless of the type of stove you choose, it must produce the proper amount of heat for the size of sauna you are building. A large stove in a small sauna can make the sauna too hot. If the stove is too small, the room may not be hot enough. It is best to consult with a stove dealer about the proper stove for your size sauna.