The best sauna wood depends on where you use it. Nordic spruce offers a budget-friendly interior, while cedar brings a distinctive scent and natural decay resistance. Aspen suits benches and panelling. Alder offers comfort against the skin, and thermally modified timber improves stability. Exterior cladding needs a separate choice, not simply more of the timber used indoors.
Choose timber for its place in the sauna
Sauna timber has to cope with heat and humidity through repeated heating and cooling. Inside, comfort matters as much as appearance. Wood with low thermal conductivity transfers less heat to your skin. Resin deserves attention too, as it can escape at high temperatures and leave surfaces sticky.
Choose your bench timber separately from the walls, then look at exterior cladding. Timber Cladding Specialists draws this distinction clearly: wood that handles British weather well is not automatically suitable for the heated room.
The sources do not agree on an overall winner. Timber Cladding Specialists favours ThermoWood pine for interiors. Midwest Sauna & Steam instead presents clear cedar alongside knotty cedar and thermo-aspen as alternatives. Where the wood will go should guide your choice, but there is still room for personal preference. A scent you enjoy or a grain you like may help settle the decision once suitability and cost are clear.
Spruce on a budget, pine with care
Nordic spruce is an affordable starting point for a traditional sauna interior. It is Timber Cladding Specialists' budget choice, and Sun Valley Saunas highlights its insulation and light Scandinavian appearance. Leisurequip also calls spruce cost-effective in some regions, with the qualification that it needs heat treatment or proper maintenance.
Look beyond the species name when buying boards. Timber offered for sauna interiors is not interchangeable with ordinary timber sold for other uses.
Pine makes that distinction especially important. Sun Valley Saunas lists it as a budget sauna wood, but Timber Cladding Specialists advises against standard pine indoors because it can release resin. Its recommendation is thermally modified pine instead. Leisurequip likewise calls for heat-treated pine or another suitable treatment. These references to pine differ in emphasis and should not be read as the same advice.
Cedar's scent, grain and grades
Western red cedar has a distinctive fragrance and warm colour. Leisurequip describes its reddish tint and natural decay resistance, while noting that it is expensive. Sun Valley Saunas lists cedar for traditional and infrared saunas.
The grade changes both the finish and the price. Midwest Sauna & Steam describes clear western red cedar as smooth and knot-free, at a higher price point. Its less expensive Select Tight Knot cedar has visible, stable knots. Those knots may expand or darken slightly over time.
Cedar's appeal does not make it the right choice everywhere. Eden Hut acknowledges its strengths but favours thermally modified timber for stability and lower maintenance, especially outdoors. If cedar's aroma and grain appeal to you, check which grade you are buying and how it needs to be cared for in the place you plan to use it.
Aspen and alder for the interior
Aspen suits benches as well as interior panelling. Leisurequip describes it as economical; Sun Valley Saunas highlights its low odour and resistance to splintering. That quieter scent may suit you better than cedar's distinctive fragrance.
Thermo-aspen has different properties from ordinary aspen. Thermal modification improves stability and moisture resistance. Midwest Sauna & Steam describes thermo-aspen as smooth and resin-free, with no scent and a uniform brown appearance. The colour may lighten with heavy use.
Alder is another interior option where comfort against the skin matters. According to Timber Cladding Specialists, it is resin-free and has low thermal conductivity, with a light, warm colour. The supplier recommends it for benches as well as walls and ceilings. There is no need to limit an interior choice to spruce or cedar.
Garden sauna cladding needs a separate decision
Outside, timber faces rain and changing moisture levels, along with sunlight and the risk of decay. These are different demands from those placed on interior benches. Timber Cladding Specialists recommends Siberian larch or ThermoWood for outdoor cladding. It warns against larch in the heated room because of resin release, and says interior-grade spruce needs treatment if used unprotected outdoors.
Eden Hut describes Thermowood as heat-treated softwood, usually Nordic spruce or pine, modified without chemicals. Its comparison favours this timber over cedar for exposed, wet conditions, particularly where stability matters.
There is no universal price ranking for heat-treated timber. Eden Hut puts Thermowood above quality cedar in upfront cost. In Midwest Sauna & Steam's comparison, thermo-aspen sits near or slightly above knotty cedar, depending on the supplier; clear cedar is its highest-priced grade. These are different products, not conflicting prices for the same material. Compare the actual species and grade, and check that each is suitable for the job.
Questions people ask
- What is the best wood for sauna benches?
- Alder is recommended by Timber Cladding Specialists because it has low thermal conductivity and no resin. Aspen is also listed for benches by Leisurequip. If you are looking at thermo-aspen, Midwest Sauna & Steam describes it as smooth and resin-free.
- Is cedar better than spruce?
- Not in every setting. Cedar brings fragrance and warm colour, with natural decay resistance, but it can be expensive. Nordic spruce offers a budget-friendly traditional interior. Choose according to where the timber will go, then weigh the appearance you prefer against your budget.
- Can you use ordinary pine inside a sauna?
- Timber Cladding Specialists advises against it because heat can release resin. Sun Valley Saunas does list pine as a budget option, while Leisurequip stresses suitable treatment. Ordinary pine should not be confused with thermally modified pine intended for sauna interiors.
- Does thermo-aspen smell like cedar?
- No. Midwest Sauna & Steam describes thermo-aspen as having no scent, unlike aromatic cedar. Ordinary aspen is described as low-odour by Sun Valley Saunas.
- Can the same wood be used inside and outside?
- Do not assume so. The conditions are different, and a recommendation for cladding does not establish suitability indoors. Timber Cladding Specialists recommends Siberian larch outside but advises against it in the heated room because of resin release.
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