How to Clean and Maintain a Sauna (UK 2026)

The single most important habit is drying the sauna out:

• Ventilate. Leave the door (and any vent) open after use so moisture escapes and the wood dries - trapped damp is what causes mould and odours. Good ventilation does most of the work for you.
• Wipe the benches. A quick wipe-down of the benches removes sweat before it soaks in.
• Always sit on a towel. The simplest preventive measure - towels keep sweat off the bench wood and dramatically reduce staining and bacteria.

Two minutes after each session prevents the vast majority of problems.

Every few weeks (or more often for a busy sauna), give it a proper clean:

• Scrub the benches and backrests with warm water and a mild, sauna-safe cleaner or a little diluted washing-up liquid. For stubborn stains, a fine sanding along the grain refreshes the wood.
• Clean the floor - duckboards and the floor below catch sweat and debris; lift and wash them.
• Avoid the wrong products. Never use bleach, strong solvents, or varnish/wood sealant on the interior - heat releases fumes and sealed wood can't breathe. Plain water and mild cleaners are right.
• Let it dry fully before the next use, ideally by running the heater briefly with the door open.

The heater stones don't last forever:

• Rearrange them periodically. Stones crack and crumble over time, restricting airflow and heat. Every few months, remove them, discard any broken or crumbling ones, and restack loosely so air and water can flow through.
• Replace them when worn. Most heater stones need replacing every year or two with regular use - our guide to sauna stones and heater care covers choosing and maintaining them.
• Use clean water for löyly. Only ever throw clean water (and approved sauna fragrances) on the stones; anything sugary or oily will burn and smell.

Mould and musty smells come from one thing: trapped moisture. Prevent them by drying the sauna after every use, keeping ventilation clear, and not leaving wet towels or buckets inside between sessions. If you do spot early mould, treat it promptly with a sauna-safe cleaner and address the underlying ventilation. For outdoor saunas, also check the exterior seasonally - reapply exterior wood treatment as needed (exterior only), clear debris from the roof and around the base, and make sure rain isn't pooling. A little seasonal attention keeps an outdoor sauna sound for many years.