Sauna maintenance

Read how to treat an outdoor sauna the right way. With proper sauna maintenance, you extend its lifespan and keep your outdoor sauna working optimally.

Sauna maintenance | About Arnita qrest showroom ArnitaZutphen showroom · writes about maintenance3 min read · updated Jan 2, 2026 3 min read Updated January 2, 2026
Sauna maintenance is the secret to a long lifespan for your outdoor sauna. Read everything about wood treatment here.
In this article2 parts

How to keep your outdoor sauna looking beautiful for years

With proper sauna maintenance (1-2 times a year), you extend the lifespan of your spa product. But what exactly do you need to do to properly protect your outdoor sauna? Below we explain everything step by step, so you can get started right away.

Wood treatment: step by step

Preferably choose a dry, mild day and avoid working in full sun. Direct sunlight can cause the product to dry too quickly, leading to blotches or streaks appearing sooner.

Step 1: Clean the wood thoroughly

Start by cleaning the exterior. Remove dirt, grime and dust, then let the wood dry thoroughly before continuing.

Step 2: Sand and remove dust

Sand the wood in the direction of the grain.

  • Is the wood rough or weathered? Then start with a coarser grit (e.g. around 80-120).
  • Is the wood still reasonably smooth? Then a medium grit (120-150) is often sufficient.

Carefully wipe or brush away the sanding dust, so that oil or stain can adhere properly.

Step 3: Applying the first coat

Stir the product well and apply a thin, even layer in the direction of the wood grain. Work neatly wet-on-wet and avoid pools or drips.
Apply the oil thinly with the grain, let it soak in for 5-15 minutes, then wipe away all shiny/wet spots with a clean, lint-free cloth (check again after 10-20 minutes) so the surface can dry to a matte finish.

Step 4: Drying and second coat

Allow the first layer to cure properly. Generally allow 24-48 hours, depending on the product and weather conditions.
Want to apply a second coat? Only do so once the first layer is completely dry.

Tip: We don't recommend lacquer for outdoor saunas. Lacquer forms a closed layer on the wood. Because the wood outside is constantly ‘working’, this layer can crack or peel over time. Instead, choose a suitable outdoor stain or outdoor oil: it protects the wood, preserves its natural look, and is generally easier to maintain and touch up locally.

Interior maintenance: simple but important

For the interior, we recommend wiping down the sauna regularly with a slightly damp cloth. After every session, sweat residue and dirt remain behind. Always let the sauna air out well afterwards: open the door/windows for a while so everything can dry completely.

Sauna maintenance. Everything about wood treatment for your outdoor sauna!

Heater and stones: check regularly

  • Remove ash residue and check that everything works neatly and safely
  • Check the sauna stones regularly: replace cracked or crumbling stones. This helps ensure good heat and prevents problems
  • Also periodically inspect the flue/chimney (and have it professionally cleaned where necessary)

! You'll know the flue/chimney needs cleaning if you notice one or more of these signs:

  • Poorer draft: the heater has more trouble getting going
  • Smoke in or around the sauna: smoky smell, backdraft when opening the door, or smoke that doesn't clear away smoothly
  • More soot buildup: black soot flakes/chimney soot near the heater, pipe connections or on the roof
  • Visible buildup: if you can look into the pipe and see a clear, thick layer of soot/tar
  • Wet/tar-like drips: brownish/blackish “tar” coming out of seams or from under the pipe

 

IMPORTANT:

! Only use well-dried, clean firewood. The most suitable wood to burn is hardwood, such as beech, oak, ash or birch. Using the right wood is also important to prevent excessive smoke, soot and tar buildup, so your flue gets dirty less quickly. !

Wellness heating wood-fired heater

Read here how to maintain a hot tub or here about hot tub water maintenance!

Sauna maintenance | About Arnita qrest showroom
About the author Arnita Arnita is an Advisor at Qrest Sauna's & Hottubs in Zutphen. Since 2022, she has been advising customers on the choice, installation and maintenance of wood-fired, electric and hybrid hot tubs, jacuzzis and outdoor saunas. Schedule an appointment More articles by Arnita
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