A sauna provides a dry-heat bath that causes a person to sweat. A residential sauna can come prefabricated, be custom built or be modular, meaning it comes in pre-made panels that are assembled. A sauna often produces about 180F of heat, so proper installation, regular inspection and taking safety precautions such as ensuring you don’t leave combustible items near the heater is paramount. There are specific requirements for saunas, specifically for ventilation, controls and heating.
Door
The door to a sauna needs to be non-lockable and open outward, according to “Architectural Graphic Standards for Residential Construction,” by Nina M. Giglio and the American Institute of Architects. The standard size door is 6-foot, 8-inches tall and 24-inches wide. This door size helps minimize heat loss and maximize space for benches inside the sauna. Due to the door’s weight, 4-inch brass butt hinges should be used. Door handles need to be made of wood.
Control and Heat
The sauna’s control box can be placed on the heater. If it is not, it needs to be put within six feet of the sauna’s heat-sensing device, according to the AIA. Controls need to include a thermostat, a timer, a heat indicator light and a light switch. Heater output capacity can vary depending on sauna room size. The general range is 1,700 to 15,000 watts. Stones that filter the heat and electromagnetic field must completely cover the electric elements. A home sauna heater must be installed by a certified electrician who is knowledgeable about local as well as national electrical regulations, according to Fino, a sauna heater manufacturer.
Construction Materials
Wood-framed baseplates need to be made of pressure treated wood. Other framing can consist of standard wood. The framing for the sauna does not extend to the ceiling of the room that the sauna is in. Metal framing is not used because it conducts heat. The sauna’s floor needs to be waterproof. Benches must have a 7-foot clear height. They generally offer a per-person width of 24 inches and a length of 72 inches, says Giglio.
Air Flow
A sauna needs to have air flow. Updraft action provides fresh air. This is created by combining an air inlet in the sauna’s wall directly below the heater with an air outlet that’s placed a minimum of 6 inches from the ceiling and 24 inches higher than the sauna’s inlet. A vent space below the door also is recommended, according to Giglio.
Interior
Finish wall surfaces and benches should be made of softwoods such as redwood and western red cedar. These keep the atmosphere dry by absorbing humidity. Wood is kiln-dried until it has a moisture content that’s between 6 and 11 percent, according to the AIA. These soft woods also do not absorb as much heat as harder woods do, making surfaces inside the sauna more comfortable to touch.
Lighting
The switch for lighting is always outside of the sauna, according to the AIA. Indirect lighting is best. A light that is slightly behind and above the sauna user’s normal field of view works best.
