Building A Home Sauna: What Should You Be Prepared For?





Before you buy a home sauna and let the workers into the house, you should ideally know in advance in which room you will build the sauna, where you will ventilate the air or where the existing electricity or water distribution lines lead. It will make the work easier for both you and the implementation company; you will also avoid having to come up with a solution at the last minute.


Read what is crucial when building a sauna.


Placing the sauna


Construction readiness for the installation of the sauna begins with choosing the room in which you will place the sauna. Most households choose a bathroom, hall or technical rooms, for example. But there are also people who install a sauna in their living room.


When choosing a room, keep in mind that the humidity of the walls and ceiling must not exceed 10%, and the atmospheric humidity in the room must not exceed 55%. This can be a complication, for example, in smaller bathrooms that do not have windows and cannot be ventilated well.


In general, we recommend that the room with the sauna can be ventilated occasionally by opening a window or at least using a mechanical fan.


When choosing a room, count with the size of the sauna, too výběru místnosti kalkulujte i s velikostí sauny. Calculate with a width of 70 cm per person; the height of most saunas is 210 cm. With such a height, you can comfortably place two tiers of benches in the sauna - the first at a height of 45 cm, the second at a height of 90 cm. Also, do not forget that the sauna door always opens outwards for safety reasons, so make sure it does not open into furniture or other doors.



Sauna walls and flooring


The walls of the room, which will serve as part of the outer shell of the sauna, must be straight (a deviation of no more than 2 mm per meter of length); if the substrate is plasterboard, it should be "green" (GKBI, RBI), which better resists moisture. Ideally, also find out where in the wall the water and electricity distributions lead and where the aluminium sections are located.


The floor is also important, as it must withstand moisture. A wooden or laminate floor is therefore unsuitable; tiles can also be problematic for saunas with wood-burning stoves, as the jointing materials are not resistant to high temperatures. However, you can solve this by putting a protective mat under the stove. If the floor is slippery, it is better if you cover it with a plastic or wooden grating.


If you have floor heating or other distribution systems in the floor, you should ideally mark in advance where they lead so that damage or drilling cannot occur during the construction of the remaining walls of the sauna.



Power supply


If you are buying a Finnish sauna with an electric heater, the heater will be the biggest appliance. Less powerful stoves for smaller saunas (approx. up to 8 m3) usually require a voltage of 230 V, while more powerful stoves require 400 V.


In addition to the heater, you will also be powering the sauna lighting (or colour therapy), a wall panel for temperature control (if you want one), and possibly a fan. For these appliances, a classic cable with a voltage of 230 V is sufficient. Also, think in advance whether you want a socket in the sauna, so that you can vacuum comfortably inside, for instance.


Read more detailed requirements for electrical installations in the manual, page 4 >>



Insulation and ventilation


Since saunas are very hot and/or humid, they are carefully insulated. Mineral wool is first placed behind the outer perimeter walls (or wooden cladding), followed by ALU foil. Then, a wooden structure made of structural beams carrying a vapour barrier is constructed, followed by the sauna's inner cladding – moulding made of spruce or aspen wood, for example.


Proper insulation of the sauna prevents heat and moisture from escaping through the walls. Therefore, it is necessary to ventilate the space in a controlled manner so that air circulates in the sauna. It is considered ideal when the air in the cabin is changed 6 times in one hour.


Po The ideal minimum for sauna ventilation is two ventilation openings 10x10 cm in size - one supply and one exhaust. The inlet should ideally be on the floor and as close as possible to the sauna stove. Another option is to make it under the door: you simply raise the door by 10 cm and leave a gap under it.

On the contrary, the exhaust opening should be as far as possible from the sauna stove, somewhere at the height of the upper bench (mentioned 90 cm), or near the ceiling. Just be aware that when it is up at the ceiling, yo will have warmer air coming out of the saun.a 


You can lead the air outlet to the same room in which you have the sauna or to an adjacent room. Expect that these rooms will be warmer during the sauna session, around 30°C. On the contrary, it is not advisable to vent the air from the indoor sauna outside the house because the air would then condense at the exhaust opening in the winter and create a lot of humidity.


Building an outdoor sauna


Outdoor saunas are more expensive and more complex than indoor saunas, but you do not have to deal with almost anything in terms of construction readiness. All you have to do is choose a suitable area in the garden and, depending on the size of the sauna, prepare a concrete skeleton, into which the installation company will then "put" the sauna for you.


We always recommend wood-burning stoves for outdoor saunas due to their better heat output, so you only need to run the electricity for lighting. However, if you would like to experience true romance, it is not necessary either - you can light the sauna with candles only, as the Finns themselves like to do.


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