Sauna construction and finishing
This page contains a description of and photos showing the various stages of construction and finishing of a sauna in our home basement. The sauna was originally rough framed about a year after we moved into our house but left un-finished because of the cost of the materials and an electrical code issue with the location of the 120 volt heater control unit that was available at the time. We recently decided it would be good to finish the project and found that the original heater control had been replaced with a low-voltage digital version that could be located just outside the sauna door. Problem solved. The sauna measures approximately 7 feet wide x 5 feet deep x 7 feet high and is lined with clear western red cedar, very beautiful wood and perfect for the application. Smells good too!
These photos show the basic framing and existing insulation on the outside wall. The polyethylene vapour barrier had to be removed and replaced with aluminum foil vapour barrier, since the poly is not suitable for the heat of a sauna and would likely give off an odour during use.
Framing is added for the inlet air vent and benches. Then insulation is added to all the walls and ceiling. I kept the existing fibre-glass insulation in the exterior wall but used mineral wool insulation for the remainder.
Next, the aluminum vapour barrier is added and stapled to the framing. It is supposed to be a bit loose, for reasons not particularly clear to me (since aluminum would expand with heat).
I wanted the finished cedar boards on the walls to be vertical rather than horizontal so, because my framing is vertical, I had to add horizontal strapping in rows spaced about a foot apart. A brad nail or two at each row of strapping provided me enough support for the tongue & groove cedar which I trimmed to length, leaving about 1/4"gap at the bottom so they would not contact the concrete floor and soak up moisture. The ceiling was nailed up first, directly to the framing which was oriented across the depth, allowing me to run the cedar boards along the 7 foot nominal width dimension. Except for the first and last pieces of each section, nails are through the tongue so they are concealed when the next board is added. Filler was used to cover any surface nail heads.
Because of the location of the sauna within my basement, I had to get creative to place the exhaust vent diagonally opposite from the inlet but allow it to vent back to the un-finished utility/mechanical equipment area where the inlet air originates. A number of options had been considered but the least disruptive to the framing and structure was to run a sloped duct inside the finished sauna, concealed under the upper bench. I built a front cover to disguise it a bit.
The heater was installed and connected by a certified electrician and inspected by the City Inspector to ensure that all was to code and validate the heater warranty. Then the benches were made from 1"x 4" and 2"x 4" clear western red cedar and installed. The exhaust vent duct is barely visible under the upper bench and doesn't detract from the look of the sauna.
The sauna turned out quite successfully, and it is a valuable addition to our home as well as a great means to promote good health, muscle relaxation and improved circulation. Now, we can enjoy these benefits right in our own home. Crank up the heat!