The short answer
- Abachi is a very light, pale, near knot-free tropical hardwood prized for sauna benches, backrests and headrests.
- It is one of the lightest timbers used for sauna seating, with a published density of about 380 kg/m³, similar to western red cedar.
- It is not durable. It suits dry interior use only and has no place outdoors.
- Its dust is a known sensitiser for the people who machine it, which, according to one Finnish sauna-design source, is one reason it has lost some favour there.
- Australian supply is uncertain, and certified sourcing should be confirmed early.
What we use
Most of the saunas we build are lined in western red cedar, and we sometimes use Canadian hemlock. Clear cedar already gives us a very light, comfortable bench, so we do not routinely build with abachi. It is a respected sauna timber that you may see in European rooms, and if you would like it for your benches we can discuss supply and detailing with you.
Origin and names
Abachi is Triplochiton scleroxylon, a hardwood native to the West and Central African forest zone, from Guinea east to the Central African Republic and south to Gabon and the Democratic Republic of the Congo. It is traded under several names:
- Abachi (common in the sauna trade)
- Ayous
- Obeche
- Samba and wawa
Because the names vary by market, specify the botanical name on any quote.
Appearance, knots and resin
Abachi is pale yellow to creamy white, with a straight or interlocked grain and a medium to coarse texture. It is near knot-free, which is part of its appeal for benches.
Two practical points follow from its structure:
- Interlocked grain can tear out during machining, so profiling and sanding need sharp tooling and care.
- Poorly processed stock can discolour or develop fungal stain, so supplier quality matters.
Resin: none reported.
Aroma
Green abachi has an unpleasant smell, but this is mostly gone once the timber is dried. Finished, seasoned boards are close to scent-free.
Thermal feel and density
Abachi’s main attraction is its low density.
| Timber | Published density | Notes |
|---|---|---|
| Abachi | About 380 kg/m³ | The Wood Database; PROTA gives 320–440 kg/m³ at 12% moisture content, and a scientific database a wider natural range of about 250–550, typically 350 |
| Western red cedar | About 340–380 kg/m³ | Range across published sources |
| European aspen | About 450 kg/m³ | For comparison |
That places abachi among the lightest sauna timbers, close to cedar and lighter than aspen, alder or hemlock. It is often described as “cooler than cedar”. Given their similar densities that is plausible, but we found no direct comparative measurement, so treat it as a claim rather than a fact.
The German manufacturer Klafs fits obeche headrests and backrests as standard in its Premium sauna, and Finnish sauna-design guidance lists abachi among the bench timbers.
Stability and moisture movement
Abachi moves relatively little. Its published full green-to-dry shrinkage is 8.7% by volume, more than western red cedar (6.8%) but less than aspen, alder or hemlock (about 11.5–13.2%). That stability helps benches stay flat through repeated heating and drying.
Durability and termites
Abachi is not durable, and sources disagree only on how much:
- CIRAD, the French agricultural research body, rates it durability class 5 (not durable), susceptible to termites, and suitable only for interior use without dampness. PROTA likewise describes it as susceptible to termites, powder-post beetles and drywood borers.
- The American Hardwood Export Council gives obeche as an example of class 4 (slightly durable).
Both are European classifications, not Australian ones, and we found no Australian durability or termite rating for abachi. The practical conclusion is the same: abachi belongs inside a heated, well-ventilated room, never outdoors or in contact with the building structure. In Queensland, where subterranean and drywood termites occur, termite management for the sauna structure is a matter for the designer and certifier.
Where abachi works
Benches, backrests and headrests
This is abachi’s purpose in a sauna. Its low density, pale colour and near knot-free boards make it an excellent seat and backrest timber. It is soft, however, so it dents under heavy use, and benches benefit from rounded edges and replaceable slats.
Walls and ceilings
Possible but unusual. Abachi is occasionally used for ceiling strips in architecture. In the Klafs Premium sauna, for example, the obeche headrests and backrests sit against spruce or hemlock panelling.
Commercial rooms
Abachi is a standard headrest and backrest timber for at least one major European maker. In a busy room, plan for its softness with replaceable slats. Commercial fabrication also needs reliable dust control, because of the sensitiser risk described below.
Workshop dust
Abachi dust is a well-documented occupational sensitiser. It has caused asthma, rhinitis and skin reactions in woodworkers, including published cases in sauna builders. A Finnish sauna-design source notes that abachi has fallen out of favour there partly for this reason and partly because of inconsistent quality.
This is a fabrication issue that calls for dust extraction and respiratory protection. The research concerns the people who cut and sand the timber; it does not show any risk to people using a finished sauna.
Ageing and care
Like every pale sauna timber, abachi darkens with use, and benches show sweat and water marks where people sit. General sauna care applies:
- Towels on benches, cleaning along the grain and light sanding for marks.
- Paraffin oil or sauna wax on benches if wanted, following the product’s data sheet, and never both on the same surface.
- No varnish or lacquer inside the hot room.
- Dry the room after use with the vent open and the door ajar.
See our care guide for detail.
Supply, legality and certification
- Australian availability is uncertain. None of the Australian sauna timber suppliers checked in our research listed abachi. Confirm stock, lead time and grade before designing around it.
- Conservation status: abachi is not listed in the CITES Appendices. The IUCN Red List’s assessment (Lower Risk/least concern) dates from 1998, and PROTA notes heavy harvesting pressure in parts of its range, so certified supply matters.
- Certification: FSC and PEFC-PAFC certified ayous is available from Central African producers. Ask for certified supply, with chain-of-custody documents for the specific order.
- Legality: Australia’s Illegal Logging Prohibition Act 2012 places due-diligence obligations on importers of regulated timber products. Ask the supplier how that obligation has been met for your order.
Advantages and disadvantages
Strengths: very light and comfortable to touch; pale and calm; near knot-free; resin-free; low movement; close to scent-free once dry.
Trade-offs: not durable, interior use only; soft, so it dents; interlocked grain needs careful machining; dust is a known sensitiser for fabricators; Australian supply and certification can be hard to confirm.
How abachi compares with western red cedar
- Feel: very similar. Both are among the lightest sauna timbers, and clear grades of either make a comfortable bench.
- Stability: cedar moves a little less (6.8% against 8.7% laboratory shrinkage); both are stable for sauna use.
- Scent: cedar is strongly aromatic; dry abachi is close to scent-free.
- Look: cedar is warm brown and varied; abachi is pale and uniform.
- Durability: Australian references rate cedar heartwood termite-resistant and durable above ground. Abachi is non-durable and, according to CIRAD, susceptible to termites.
- Supply: clear cedar is readily available in Australia; abachi is not.
- Workshop dust: both are known sensitisers for the people machining them.
For more, see our western red cedar guide and the timber hub.
Compliance and licensed trades
In commercial and multi-residential buildings, linings may be subject to National Construction Code fire hazard requirements, and overseas fire classifications are not Australian ones. Confirm timber selection with the designer and building certifier, and follow the heater manufacturer’s clearances to timber.