Sauna benches can last for decades with proper care, but many people end up replacing their bench boards too early. Heat, humidity, and regular use stress the wood, but with simple maintenance procedures, you can significantly extend the lifespan of your bench boards. In this article, we explain why bench boards wear out quickly, how cleaning and moisture management affect durability, and which repair measures are worth doing yourself.
Why bench boards wear out quickly in saunas
Sauna conditions are extreme for wood. Temperature varies from room temperature to over 80 degrees Celsius, and humidity rises rapidly during steam sessions. This constant fluctuation in temperature and humidity causes the wood to expand and contract, which stresses the wood’s structure.
The most common causes of premature wear of bench boards are inadequate ventilation and neglecting regular cleaning. When moisture remains in the sauna for extended periods, the wood absorbs it and begins to develop mold or staining. Body oils, sweat, and soap residues form a layer on the wood surface that collects dirt and bacteria.
Aspen and alder are popular sauna woods due to their low thermal conductivity. They don’t heat up as much as pine, for example, but still require regular maintenance. Heat-treated wood withstands moisture and heat better than untreated wood because during heat treatment, the wood’s structure changes and water and resin are removed from it.
Proper cleaning keeps bench boards in good condition
Regular cleaning is the foundation of bench board maintenance. Clean the benches after each sauna session with warm water and a soft brush. This removes sweat, body oils, and other impurities before they can penetrate deeper into the wood.
For weekly thorough cleaning, citric acid or oxalic acid is sufficient. Mix about 100 grams of acid into 10 liters of warm water. Apply the solution to the benches, let it work for a few minutes, and rinse thoroughly. The acid removes stains and kills bacteria without damaging the wood’s structure.
Avoid strong detergents and chlorine-based products. They can damage the wood surface and leave harmful residues. Also, don’t use a pressure washer, as it can damage the wood surface and push dirt deeper into the wood.
Allow the bench boards to dry thoroughly after each cleaning. Open the sauna door and any windows so air can circulate. Wet benches are a favorable breeding ground for mold and bacteria.
How moisture affects the durability of bench boards
Moisture is the greatest enemy of bench boards. When wood absorbs moisture, it swells and softens. If continued for long periods, moisture causes molding, bacterial growth, and weakening of the wood structure.
Effective ventilation is the most important means of moisture control. The sauna must have both supply and exhaust ventilation that changes the air several times per hour. Supply air is usually taken from near the stove and exhaust air is directed away from under the bench levels.
After using the sauna, leave the door and windows open for at least an hour. This speeds up drying and prevents moisture from condensing on the wood surface. In summer, when outdoor air is humid, it’s worth using a fan or dehumidifier.
Regularly check that the sauna’s waterproofing is in good condition. Water damage from the floor or walls can moisten bench boards from below, making moisture less likely to evaporate.
Simple repair measures for restoring worn bench boards
Small defects in bench boards should be repaired immediately before they worsen. Dark spots and stains can often be removed with fine sandpaper (grit 180–220). Always sand in the direction of the wood grain and lightly so you don’t damage the wood surface.
Deeper stains require stronger treatment. Try citric acid or oxalic acid as a more concentrated solution. Apply acid to the stain, let it work for 10–15 minutes, and rinse thoroughly. Repeat if necessary.
Small cracks and chips can be repaired with wood filler designed for sauna use. Fill the crack with filler, level the surface, and let it dry according to instructions. Fine sandpaper will smooth the final result.
If bench boards have extensive mold spots, deep staining, or structural damage, repair is usually not worthwhile. Replace damaged bench boards with new ones. Replacing one or two bench boards is more economical than replacing the entire bench package later.
Properly maintained benches last for decades and provide a pleasant sauna experience. Regular cleaning, moisture management, and small repair measures keep sauna wood in good condition for a long time. We at Pieksäwood manufacture high-quality aspen and alder benches that withstand the demanding conditions of saunas. Our over 75 years of experience in the wood products industry and 20 years of heat treatment expertise ensure that you get long-lasting and beautiful bench boards for your sauna. Contact our sauna experts to learn more about our bench board options.