How to Clean and Seal Home Sauna Benches

Sauna benches take sweat, heat and moisture every session. Looked after properly, untreated timber benching lasts decades. Treated wrongly, it stains, greys and starts to smell within a year.

Never varnish, lacquer or polyurethane the inside

This is the single most common mistake. Film-forming finishes trap moisture, blister at 90°C and can off-gas into the air you are breathing at the hottest point in your week. Inside a sauna, timber should stay untreated or be finished only with a sauna-grade paraffin oil made for the job.

The weekly routine

1. Wipe benches down with a damp cloth after heavy use — plain warm water.

2. Once a week, use warm water with a mild, fragrance-free soap, then rinse.

3. Leave the door open and the ventilation running until the room is fully dry.

4. Always sit on a towel. Sweat, not heat, is what stains timber.

Twice a year

Lightly sand benches along the grain with 120-grit to lift surface stains and raise a clean face.

Vacuum the dust, wipe with a damp cloth, let it dry completely.

Apply sauna paraffin oil thinly with a lint-free cloth, then buff off the excess. Two thin coats beat one heavy one.

What not to use

Bleach or chlorine cleaners — they attack the fibre and linger in the air.

Pressure washers — they drive water deep into the grain.

Decking oils and outdoor stains — they are not rated for sauna temperatures.

Why timber choice matters

We line saunas in low-toxin Modinex zero-waste timber and keep treated timber well away from the inside of the vapour barrier. Treated timber and 90°C heat are a bad combination, and no maintenance routine fixes a bad specification.

Build it right and the maintenance is ten minutes a week.

How to Clean and Seal Home Sauna Benches