Sauna Wood

For most home saunas we recommend Thermo‑Aspen, Thermo‑Alder, Aspen or
Thermo‑Spruce. All of them are proven in high‑heat, high‑humidity
environments and offer a cleaner, more stable result than standard
construction pine. Your choice comes down to budget and whether you want
a light, warm or dark interior.

Bench wood should be smooth, low‑resin and comfortable against skin.
Aspen, Alder and Thermo‑Spruce bench profiles are all excellent options.
Avoid pressure‑treated lumber or interior paneling that was never
designed to run at sauna temperatures.

Yes. Many of the nicest saunas use a mix – for example, Thermo‑Spruce
walls with light Aspen benches, or dark Thermo‑Alder walls with matching
benches and black accent walls.

Our go‑to “no‑compromise on performance” budget combo is Thermo‑Spruce on
the walls and ceiling with Thermo‑Aspen benches and backrests. For a
modern Nordic look, run Thermo‑Aspen on the walls and benches and use a
black Thermo‑Spruce or Black Alder accent wall behind the heater.

The short answer for most home saunas is: no, treatment is not
required. In Finland it’s common for home saunas to be left
completely unfinished, with bathers sitting on towels and simply cleaning
the wood as needed so it can breathe and dry quickly.

For detailed recommendations, see the care guide in the
attachments section on each individual wood page. There you’ll find
species‑specific tips for cleaning and optional protection.

For commercial saunas, rental spaces, or if you want to keep your sauna
looking new as long as possible, we recommend
paraffin oil or sauna wax along with
sauna‑safe cleaners. You’ll find them in our accessories
section. They ship for free for life with Sauna
Marketplace heater orders – even when you reorder later.

Standard stains, polyurethane and exterior sealers are not recommended
inside a hot sauna. Always check the product label or ask us before
applying any finish.

As a rough rule of thumb, a 6×8 ft indoor sauna usually needs
enough cladding for all four walls plus the ceiling, plus bench boards
for 2–3 tiers of benches. Exact quantities depend on your layout,
ceiling height and board profile.

The easiest way to avoid over‑ or under‑ordering is to send us a sketch
or measurements. We can help you build a simple cut list and recommend
lengths that minimize waste.

We love a good cedar sauna, but we don’t sell Western red cedar boards
online for a few reasons.

• Quality is hard to guarantee at a distance.
  It’s almost impossible to source cedar in the consistent, high quality
  we expect when we’re shipping it across the country. You’re usually
  better off finding cedar locally where you can see the boards in
  person.
• Our thermally modified woods perform better.
  Once people experience thermally modified aspen, alder and spruce, they
  almost never go back to cedar. Thermo woods are extremely stable, so
  they don’t develop the same gaps and cracks you often see in Western
  red cedar over time.
• Durability and rot resistance.
  Properly thermally modified sauna woods are more resistant to rot and
  decay than even old‑growth cedar, especially in demanding, wet or
  heavily used environments.
• Sensitivity and dust.
  Many people are allergic or sensitive to Western red cedar. Among folks
  who work with WRC every day—loggers, mill workers, carpenters, etc.—
  studies suggest roughly 5–10 % develop
  sensitization or asthma related to WRC dust.

So if your heart is set on cedar, we genuinely think you’re best served
by sourcing it locally. If you’re open to alternatives, our thermally
modified sauna woods usually win people over for good.

If you love the look of Western red cedar, we have two great analogs:

• Thermo‑Spruce is closest to a knotty, rustic Western
  red cedar board. It has a warm, reddish‑brown tone with visible knots
  and a cozy, traditional feel.
• Thermo‑Aspen is more like a clear, Grade‑A WRC with a
  smoother, more uniform appearance and very few knots.

Both options give you that warm cedar‑style tone with the added stability
and durability of thermally modified wood.

Unless there’s a special stock note when you add a sauna wood product to
your cart, that wood is in stock in the US. In most
cases we expect delivery to occur within 10–14 days of
your order.

Heavier orders and remote locations can take a bit longer, but if timing
is critical for your project, reach out before you order and we can
confirm current lead times.