Materials guide

Sauna wood: the guide your joiner would approve

The timber is 70% of the experience: the scent when the door opens, the bench that doesn't scald your leg, the wall that crosses decades. We compare the four we use - and list the three that show up in other people's quotes and deserve a flat no.

Materials guide · 8 min · 2026-09-07

Golden rule: walls want light, stable, aromatic timber; benches want low thermal conductivity; outdoor faces want brute resistance to sun and rain. No single wood wins all three - which is why a good sauna combines two or three species.

The four in our joinery

Timber	Best at	Why	Watch for
Pale cedar	walls and ceiling	light, stable, the classic sauna scent	insist on knot-free selection
Cumaru	benches, decks, outdoors	dense, lasts decades in Brazilian weather	benches need machining so they don't run hot
Thermowood (pine/ash)	walls and outdoors	baked at 200 °C: won't warp, won't rot	the caramel tone darkens - plan it into the design
Aspen	benches and backrests	pale, soft, zero resin - never burns skin	imported: longer lead time, higher price

The three to refuse in any quote

Raw pine 'autoclave treated': resin turns to hot droplets at 90 °C, and the treatment's CCA has no business in a hot, closed room.
'Veneered' MDF/plywood: glue and heat are enemies - it delaminates, off-gasses formaldehyde and smells of new furniture forever.
Plain eucalyptus without engineering: it moves too much; in six months the wall gaps tell the story.

Combinations we deliver

The classic duo: pale cedar on the walls + cumaru on the benches - one's aroma, the other's longevity (see the dry sauna). For estate outdoor builds: thermowood on the weather faces + cumaru on the deck. A minimalist interior calls for pale aspen from wall to bench - the favourite of architect-led projects.

Brazilian cedar or western red cedar?

We work with certified-forestry pale cedar and, on request, the Canadian - the aroma is kin, the project decides. Knot-free selection matters more than the log's passport.

Does dark timber run hotter?

On the bench, yes - which is why a dark bench (cumaru) ships machined with ventilation gaps and calculated thickness. On the wall, colour is aesthetics: what touches you is the backrest, which we make pale.

How long does a well-built sauna last on the coast?

With the right species and annual treatment: decades. Our 3-year warranty is the start of the conversation, not the end.

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