What is the one post-sauna ritual that could be silently rotting the heart of a Finnish home? According to a specialist, a widespread cleaning habit is causing significant, hidden damage to sauna structures, shortening their lifespan through accelerated wood decay. Tapani Aho, the managing director of the interior sauna company Saunastore, reveals the most common errors and provides concrete advice for proper sauna care, drawing on direct experience from customer cases.
The Hidden Cost of a Thorough Rinse
After enjoying the löyly, many people think the sauna needs a good rinse. Water is thrown or sprayed liberally onto the benches, walls, and sometimes even the ceiling. Aho warns this practice is harmful. He recalls a case where a customer's sauna benches had darkened in less than two years. 'When you lifted the bench, there were fist-sized mushrooms growing underneath,' Aho said. 'What could be a more favorable condition for fungus to grow than in a warm, moist, and slightly dark space.' It turned out the owners were accustomed to spraying down the entire sauna with a shower hose after use.
Aho is currently replacing benches for a company whose sauna has showerheads in the ceiling. A mist shower in a sauna might sound luxurious, but in reality, it shortened the service life of the benches because they were constantly damp. 'Wood requires and needs to be able to dry between sauna sessions and preferably as soon as possible after sauna use,' Aho explained. He emphasizes that the core issue is preventing the wood from remaining wet for extended periods, which creates an ideal breeding ground for mold and structural weakness.
Proper Cleaning Over Power Washing
Instead of rinsing, Aho recommends cleaning the benches by wiping them with a damp cloth. He advises using bench linen covers, as they reduce the need to wash the sauna itself. A full wash of the sauna is recommended only a couple of times a year, during which it will naturally get wet. 'In that case, it's good to turn the stove on for a short while after washing so it dries the moisture out,' Aho noted. This targeted approach to cleaning focuses on surface dirt without saturating the wood's core, preserving its integrity and natural antibacterial properties that are part of a well-maintained sauna's character.
The Critical Role of Drying and Ventilation
For the sauna to dry properly, it is crucial to keep the sauna door closed after the löyly, Aho points out. 'The sauna stove is capable of heating the sauna air and drawing moisture out of the benches and from everywhere. The moisture is removed through ventilation,' he said. If the sauna door is opened, the warm air escapes into the bathroom. This causes the sauna to cool down too quickly, which in turn slows the drying process. Aho states that only in cases where the ventilation in the sauna is weak is opening a door or window justified.
He admits to opening the sauna door himself, but only about an hour after sauna use, when the sauna has certainly had time to dry. 'I take, so to speak, additional heat from there into the bathroom, which speeds up the bathroom's drying. Our washroom is on the ground floor and a bit too cold, as it is not always in use,' he shared. This practice highlights a nuanced understanding of heat and moisture transfer within the home, using residual sauna heat efficiently only after the primary drying cycle for the wood is complete.
Why Good Intentions Lead to Damage
The analysis of this common mistake reveals a cultural paradox. Finns, renowned for their sauna expertise passed down through generations, are often misled by an instinct for cleanliness. The intention to rinse away sweat and maintain hygiene is fundamentally good. However, it conflicts with the material science of wood, a living, breathing material that defines the authentic sauna experience. The ritual of splashing water after sauna, perhaps seen as a final purification act, ironically initiates a process of decay. This happens because modern, tightly built saunas may not have the same passive drying capacity as traditional, more ventilated log saunas, making post-use care even more critical.
Furthermore, the increasing installation of luxury features like built-in steam or mist systems, without clear guidance on their impact on maintenance, compounds the problem. Aho's cases show that technology intended to enhance the experience can undermine it if the fundamental need for wood to dry is overlooked. The solution lies not in abandoning cleaning, but in refining the method—shifting from a flood to a gentle wipe, and from immediate cooling to controlled, stove-assisted drying. Ultimately, preserving the sauna is about understanding its nature: it is a place of extreme heat and steam that must, by design, return to a state of dry warmth, ready for the next session of löyly.