Having a sauna of your own is something that many of dream of. The problems is that building it yourself can be quite difficult as there are many building regulations that you have to take in to account with a sauna. You need to take care of the vapor insulation and also the heat insulation, while at the same time building a comfortable room that can be used as a steam room.
Because there is a heater, you need to pay attention tot the fire safety, and depending on what type of sauna heater you choose – electric or wood burning – you will need a chimney or not. Generally people will say that a wood burning sauna heater provides a better experience, but is much more inconvenient than a regular electric sauna heater.
When you are building an outdoor sauna, you will need to decide on whether you are going to build it from the scratch, or get a sauna kit. Depending on the type of kit you choose you will have a different amount of work to do. There are so called DIY-kits where you will get the timber and the materials needed, and you will also get the plans for the sauna. You will have to know how to use the circular saw as the parts are not pre-cut, and you will have to know how to take correct measurements to avoid making mistakes while cutting the wood.
The problem with these saunas is that there is a lot that can go wrong, and unless you are experienced in building you are going to have a hard time making it work.
If you are building the sauna for your own personal use, a sauna of 4’x4′ is often enough as it will easily seat 3-4 people. For larger needs you can just build a bigger room, but you will have to take this in to account when choosing the sauna heater. A larger sauna needs a bigger wood heater, or a more powerful electric heater.
How big does it have to be?
The most important thing you have to think of, is the amount of people using the sauna. You can easily be tempted to build a large sauna, but face the fact – if you are only using it alone, or with one or two family members at a time, you don’t need a sauna that can seat 15 people or more. It is not going to be energy efficient, but it can be done.
For someone looking to build a very large sauna, we recommend doing it from the beginning all by yourself, or hiring a contractor to do the work for you. You can’t find a pre-built outdoor sauna kit that is very big.
We recommend that you get at least 1.5′ of bench per person using the sauna, but if you wish to lie down while using it, you should go with much more – it is easy to count once you measure how tall you are!
Generally you can use up to two levels of benches to still get a good steam room at each of the levels, and you should not go higher or much lower than 7′ in height of the room. Having two benches, each 1,5’x3 will only give you a sauna of 2 people as you don’t want someone to be sitting on the top of your feet! If you plan on having people in both of the levels, add some space for them in either the width of the bench of the length. Having an outdoor sauna that is too small will easily make people feel claustrophobic, as the heat will further increase the effect!
Building the outdoor sauna
You will need to build the room for the sauna, and the best way to do it is to start from the basics. Depending on the area you are going to build the sauna on, you will have to make the proper foundation. After that it is recommended to do a 2×4 framing while using fiberglass insulation between the exterior paneling of your choice, and the indoor paneling which is usually chosen to be red cedar wood. You will also need a layer of wide aluminium foil under the interior paneling. This will act as a heat insulator, and give the sauna a fireproof layer.
You will have to make an air intake at the bottom of at least one of the walls which is at least 3″x3″ in size and another one on the ceiling. Put the lower vent near the heater, and the top vent in the opposing corner. Usually both of these are open at all times to avoid the loss of fresh air in the sauna. We recommend you also build a window in the sauna to allow better drying after use.
The room hight is recommended to be 7′ high as this will not weaken the steam. A too high room will cause the steam and the heat to ‘escape’ to the top of the room and you will not have such a good sauna experience. Using a 2-level design for the benches you will get the best possible layout. This way if one feels too hot in the sauna, they can sit on the lower bench, without having to compromise the experience from the other people in the same sauna.
For a small, few person sauna, it is recommended to build the benches in an L-shape, where as larger saunas that can hold from 6 to 12 peeople at a time, other possibilities exist.
You can put the benches on opposing walls, and have the sauna heater placed at the center of the sauna, or in the middle of the end wall. This will usually require a sauna at least 7’x9′ to make it comfortable. A U-design is also possible for the sauna benches, where the sauna heater would be at the open end. For this bench design, you should use a larger sauna room than 7’x9′, and a 8’x10′ is a recommended minimum. This way the room can seat up to 15 people when at maximum capacity. Generally these designs will only work with large sauna rooms, as they can cause the small sauna room to be too tightly packed.
The easier solution – pre cut sauna kit
So you are not that experienced with construction, but you think you can handle building a sauna. The best way to go is to get a pre cut sauna kit. The most commonly used timber for these is cedar wood, and it does work really well in a sauna as it dries up really quickly, and it also provides the smell that is usually associated with steam rooms. Because it is very durable and mold resistant, it is possibly the best choice for a sauna.
Most of the sauna kits that are available, are meant for a ready built room, and all they provide are the benches and the door. You can usually choose if you want to get it with the door and the heater as well – this usually drives the price up quite a bit.