The wood guide: what survives 90 °C inside and Bali outside

A sauna asks contradictory things of wood: stay dimensionally calm through 30→90 °C swings, hold no scalding resin, smell good for a decade, and - in this climate - shrug off fungus and termites the moment the heater is off. No single species does it all, which is why our builds mix four.

Western red cedar - the interior king, imported for a reason

Cedar is the classic sauna interior: light, knot-free grades, thermally calm (cool enough to lean on at 90 °C), naturally rot-resistant, and the scent guests recognise with their eyes closed. Indonesia grows no true equivalent, so we import it - and reserve it for where it earns: interior cladding and matching barrel tubs. When a budget needs trimming, cedar walls with local benches beat cedar everything.

Teak (jati) - the outdoor immortal

Plantation teak is Indonesia's gift to this trade: dense, oily, nearly indifferent to rain, insects and time. We use it for tub bodies, doors, exterior cladding - and it is the default for ice bath staves. One honest caveat: in full sun teak surfaces get hot, and its density makes it wrong for sauna benches - high thermal mass burns thighs at 90 °C.

Mahogany (mahoni) - the bench specialist

Low resin, moderate density, smooth grain: plantation mahogany makes benches, backrests and trims that stay comfortable at temperature. It is our local answer to imported abachi - at a fraction of the logistics.

Bengkirai - decks and wet zones

Hard, dense, slip-resistant when ribbed: bengkirai takes decks, platforms and wet-zone floors around tubs and plunge pools. Too hard and too hot for interiors; unbeatable underfoot.

The detail that outlives species choice

• Twin-shell ventilated walls: the humidity outside must never meet the heat inside your wall cavity - this, not species, is what kills tropical saunas.
• Stainless 316 fasteners throughout - anything less streaks black within a year of salt air.
• Oil, don't varnish: film finishes blister at temperature; penetrating oils renew in an afternoon. Twice a year, taught at handover.
• Ground contact is for stone and stainless feet, never end grain.

Species questions usually resolve in one photo of your site - send it via contact and we answer with a materials sheet. For how wood pairs across a whole circuit, see contrast therapy sets.