Clean Simple, Stay Safe
A sauna is one of the easiest spaces in your home to maintain — if you follow the right rules. The golden rule is this: water only. No chemical cleaners, no detergents, no bleach, no disinfectant sprays. The interior of your sauna gets hot — very hot — and any chemical residue left on the wood or benches will release fumes the moment the room heats up. Those fumes are unpleasant at best and harmful at worst. Plain water, a stiff brush, and a little elbow grease are all you ever need inside.
Cleaning the Interior
After Every Session
Good habits after each use make deep cleans rare. While the room is still warm and the wood is open-grained, do the following:
- Wipe down the benches with a damp cloth — warm water only.
- Leave the door slightly ajar so the room can air out and moisture can escape. This is the single best thing you can do to prevent mildew.
- Shake out or hang any towels used on the benches.
Monthly Deep Clean
Once a month — or whenever the benches look grey or feel grimy — give the interior a proper scrub:
- Mix a bucket of warm water — nothing else, just water.
- Scrub the benches and backrest with a stiff natural-bristle brush, working along the grain of the wood. Pay attention to the edges and undersides of bench boards where sweat accumulates most.
- Wipe walls and the floor with a wet cloth or mop. Again, water only.
- Rinse with clean water and let everything air dry completely before the next session. Leave the door open.
If there are stubborn grey patches on the benches, a fine sandpaper (120–180 grit) used lightly along the grain will bring the wood back to fresh. Follow with a rinse and a full dry-out.
The One Rule You Must Never Break
Never apply lacquer, varnish, paint, or any coating to the interior wood surfaces — not the benches, not the walls, not the floor. It might seem like a good idea to protect the wood, but in a sauna it is the opposite. A coating seals the wood so it cannot breathe, traps moisture underneath where it will rot, and releases toxic fumes at sauna temperatures. The interior wood must stay raw and uncoated, always. This is true for teak, cedar and pine alike.
Caring for the Exterior
The outside of your sauna is a different story — especially if it lives outdoors. Exterior cladding faces rain, UV, humidity and temperature swings every single day, and it needs a protective oil to stay healthy and looking good.
How Often to Oil
The right frequency depends on your wood and how exposed your sauna is to the elements:
- Teak exterior: 1–2 times a year with a quality teak oil. Teak's natural oils give it excellent weather resistance, so it needs the least attention of our three woods.
- Shou sugi ban pine exterior: 2–4 times a year. The burned surface protects the timber, but still benefits from regular oiling.
- Red cedar exterior: 3–6 times a year. Cedar weathers and fades faster in Thailand's climate and needs more frequent attention to stay in good condition.
A simple rule of thumb: check the exterior quarterly. If the wood looks dry, faded, or patchy — oil it. Don't wait for it to crack.
How to Apply Teak Oil
- Make sure the surface is clean and dry — brush off any dirt or debris with a dry cloth first.
- Apply the oil with a clean cloth or brush, working along the grain.
- Let it soak in for 15–20 minutes, then wipe away any excess so the surface doesn't become sticky.
- Allow to dry fully before the next rain hits — ideally choose a dry day with no rain forecast for 24 hours.
A Few Extra Tips
- Use bench towels every session. This is the easiest way to keep the benches clean — sweat goes into the towel, not the wood.
- Check the door seal and hinges monthly. A small amount of water-resistant grease on metal hinges keeps them moving freely.
- After heavy storms, check the roof and any exterior joints for standing water or dark damp patches on the cladding. Catching moisture early is far cheaper than replacing boards later.
Follow these simple steps and your sauna will stay fresh, safe and beautiful for many years. If you have questions about maintaining your Sisu Sauna, write to us at sales@sauna.in.th — we are always happy to help.