Sauna maintenance guidelines

Sauna installation guidelines


  • Read the user manuals for the sauna materials and the installation guides for all electrical devices to be used
  • Check that there is adequate ventilation in the room where the sauna is to be installed
  • Make sure that the wooden materials won’t come into constant contact with water, for instance at the bottom of the wall, during installation
  • Ensure that the external surfaces of the sauna won’t remain exposed to water or moisture upon installation
  • Ensure that any electrical work, including installation of the electric sauna heater, is done by a licensed electrician


  • It is obligatory to treat the wooden parts with special liquids to protect the wood from moisture. Treatment liquids are available in well-equipped construction stores. The manufacturer is not responsible for the products which are damaged due to the lack of protective treatment or incorrect installation.
  • Dust all of the wooden sauna components and then clean them with a sauna detergent before allowing them to dry
  • Treat the walls and ceilings on both sides with a specialist sauna finish product such as Tikkurila Supi Saunasuoja and then treat all surfaces of the seating materials with a sauna bench protection product like Tikkurila Supi Laudesuoja
  • Don’t use paints or varnishes, as the wood must be able to breathe


  • Ensure that the heater is installed according to the manufacturer’s instructions
  • Install the heating stones as directed by the manufacturer and make certain that the heating elements aren’t visible, as pouring water directly onto them can reduce their lifespan
  • Wash the heating stones to remove any production chemicals
  • Important – do not use your sauna when heating it for the first time!
  • During the first heating, do so under supervision to a temperature of about 100°C for two hours, keeping the sauna well ventilated both during and after heating; the heat will cause the wood to absorb the treatment products, which will form a protective layer


Advice for sauna maintenance


  • Only throw water on the heater, not on the walls or benches
  • Don’t wear wet swimsuits in the sauna, as water from these will damage the bench
  • To keep the bench fresh, we recommend using seat covers – these can also make it more comfortable to sit on the bench when it is hot
  • Keep an eye on the heating stones, as they may crack over time – whenever necessary, they can be replaced or
    more stones can be added


  • Wipe the benches with a clean, damp cloth – don’t use running water to clean them, and ensure that excess water doesn’t pool on the wooden surfaces
  • Use appropriate cleaning products for the benches and other wooden components, reading the instructions first
  • After cleaning your sauna, allow the surfaces to dry and ensure that the room is well ventilated – we recommend leaving the heater on for at least half an hour with the air vent open and the door and windows closed
  • If possible, lift up the benches to allow them to dry better


  • Treat the sauna’s wooden surfaces with an appropriate product (see Treating wooden components above) – this should be done more frequently if the sauna receives intensive use
  • Clean all surfaces of the seating materials, walls, and ceilings using a soft brush or cloth and a specialist cleaning product, following the instructions on the packaging
  • For deeper stains and soiling, gently clean the bench using a fine sandpaper before treating the sanded surface with a wood preservative (see Treating wooden components)
  • Avoid using cleaning agents that are unsuitable for saunas – for example, disinfectants bleach the wood and can spoil its surface
  • Inspect the fastenings on the benches and supports, tightening any screws if necessary; they may loosen over time due to changes in the wood caused by heat and humidity


  • Don’t dry textiles in your sauna, as this can be a fire hazard – excessive moisture can also damage the surface of the wood
  • Avoid heating the sauna beyond the maximum temperature specified by the heater manufacturer – excessive heat may create a fire risk or cause the wood to warp
  • Never use a pressure washer or running water when cleaning your sauna, as excessive moisture can permanently damage the structure and surface of the wood


  • Wood is a natural material, and its surface may crack or bend when used in the sauna
  • This is normal due to the extreme and rapid changes in temperature and humidity that occur
  • The risk of wood deformation depends on the material and intensity of use – the effects are also more visible in wider boards
  • Wooden materials in the part of the sauna most exposed to the hot steam may darken over time
  • When new, thermally modified wood may give off a noticeable scent as the sauna is heated, but this will diminish over time


Suggestions for using intensely thermally modified wood

Thermory’s range of wooden sauna products includes a large selection of thermally modified products. Of these, the most exclusive and luxurious items are made with wood that has undergone intense thermal modification, which gives it a beautiful rich brown color, such as dark alder and radiata pine. These elegant materials can be sensitive, and they require special care and attention to maintain their appealing properties.

  • Handle packs of wood or individual boards with care during installation
  • Don’t scratch the surface of the wood or slide the boards over one another
  • Thermally modified wood has a distinctive scent that diminishes over time but never fully vanishes – however, it will lose this scent more quickly if the sauna is heated for an extended period while being ventilated
  • Treating the wood with a suitable wood oil or care product will also soften the scent
  • Avoid washing untreated thermally modified wood with water, as this will intensify the scent
  • Please note that we cannot accept claims about the quality or scent of the wood after it has been cut, installed, or treated


Recommended maintenance supplies

Our product range includes cleaning and maintenance products suitable for both sauna paneling and bench boards.

see the care products