How to Convert a Shed Into a Sauna
How to Turn a Shed into a Sauna
This article describes how to turn an existing shed or outbuilding into a sauna. The following information is covered:
- Vapor barrier
- Interior wall boards
- Wood stove
The Shed We Converted Into a Sauna
My sons and I had been talking about turning that small shed in the back yard into a sauna for years. Finally in the fall of 2009 we made our move. We each did some research and then set to work building a sauna of our own. Read on to discover how to turn an old shed or an outbuilding into a sauna.
View of Insulation, Moisture Barrier and Cedar Wall Boards
The first thing we did was to get some insulation for the walls of the shed which we were converting into a sauna. We used rolled, fiberglass insulation for both the walls and ceiling. Insulation is described in terms of its “R” value. R13 is good for the walls of a sauna and R26 for the ceiling. Use the same insulation in the ceiling as for the walls, using two layers running the top layer perpendicular to the previous layer.
Aluminum Foil Moisture Barrier
The Moisture Barrier
Next came the moisture barrier for the sauna which is made of aluminum foil. These specially made foil barriers can be hard to find and are expensive. We solved the problem. Gordon Food Services sells large rolls of heavy duty aluminum foil. We built the sauna in 2009 and now it is 2013. I’m still using the aluminum foil in the kitchen. The foil used as a moisture barrier for the sauna must be put on with the shiny side facing the interior of the sauna so that it reflects the heat back into the room.
Installing the Ship-Lap Cedar Wall Boards
The Cedar Wall Boards
Next we looked for cedar boards for the interior. We could have gone to a lumberyard and gotten tongue and groove boards, but those are expensive. My sons looked around and found a small, local mill that had a stack of unfinished cedar boards sitting outside. We had the boards planed and brought them home. The question now was, how we would connect the boards. Would we tongue and groove them ourselves, overlap them or find another way? As we discussed it, we came up with a design that we later found actually has a name. It is called shiplap, and it is made by cutting the edge of the board into an L shape. On each edge of the board, the L faces the opposite direction. As the boards are put into place, opposite facing Ls overlap. Our sauna was becoming a reality.
Ship-Lap Cedar Wall Boards
Preparing the Door
The Wood Burning Stove
The sauna stove was the next part that needed to be done. We covered the wall space near the stove with cement board and in addition we lined the wall closest to the stove with paving bricks stacked on edge. You will need to check local codes for the distance required between the sauna stove and wall. We ran the stovepipe through the wall at stove level and then up the outside of the building. This required a lot of custom work that wouldn’t necessarily be helpful to anyone else. Be sure to get the proper pipe for going through the wall, as it needs to be double walled pipe so that the heat is reduced where the pipe comes into contact with the wall. Also remove any material on or in the wall around where the pipe passes through that is not fireproof. If it is even close, it will catch on fire.
If you are planning to convert a shed into a sauna, the floor might take some special attention. The work on the floor ranges from replacing it to doing nothing. What is the condition the floor before beginning work? Are there gaps between the boards? Is it already a tight fit?
The floor of our shed had half-inch gaps between the floorboards. This was going to allow lots of cool air to enter our sauna, thereby making the lower part cooler than the upper. We chose to use fiberglass strips and resin. The problem has been that the finished floor holds a lot of heat. I suggest laying down well-sanded boards on the old floor and installing a drain. The sauna's heat will dry the wood, preventing any problems associated with moisture.
Another suggestion is to pour a concrete floor and install a drain. Over this, install raised, slatted wood floors. These could even be removable for cleaning purposes.
The Finished Sauna: A Job Well Done
Enjoying the First Sauna
The Stove and BTUs
Choosing the sauna stove is quite complicated it seems. It depends on the construction of the sauna, window and door space, ventilation, outdoor temperatures and the construction of the sauna stove itself. The figures for determining the BTUs needed to heat the sauna are as follows: Cubic feet to be heated (Length x width x height = Cubic feet); Temperature change (Maximum desired inside temperature minus the lowest expected outside temperature). Follow the link below, enter the data and get your BTU information.
- BTU Calculator
Calculator to estimate the amount of BTU needed for the heating of your space based on the size and temperature change. Also find hundreds of other free online calculators here.
Ventilating the sauna
We chose to put one vent in the sauna, and we located it near the ceiling on the opposite end of the sauna from the door. At the bottom of the door we allow outside air to enter the sauna while the warm air escapes through the vent near the ceiling of the sauna.
As Simple as That
A sauna is relaxing and fun to use. When you entertain guests at your house, have them bring their swimsuits along so you can all enjoy a sauna together. Good luck on your next Do-it-yourself project, whether it is turning an outbuilding into a sauna or some other cool addition to your home.