Best Wood for a Sauna: Cedar vs Hemlock vs Spruce and More

The wood inside a sauna decides how it smells, how hot the bench feels on bare skin, how it holds up to years of heat and moisture, and a real share of the price. Here is how the six common sauna woods compare, and which one fits the way you plan to use yours.

Sauna wood types compared

Cost bands are relative estimates for the same size cabin; actual prices vary by grade, board thickness, and supplier.

Cedar: the durable default

Western red cedar is the most common sauna wood in North America for good reason. The USDA Forest Products Laboratory's Wood Handbook classes cedar heartwood among the most decay-resistant domestic woods, which is exactly what you want in a room that swings between dry heat and damp cool-down every session. It is also dimensionally stable, so walls and doors are less likely to warp.

Watch for: the smell is strong at first and fades over months. Cedar dust and oils can also bother sensitive airways. Occupational studies of mill workers link heavy western red cedar dust exposure to asthma (see this NIH-hosted study). A finished home sauna is a very different exposure than a sawmill, but if you have asthma or known wood allergies, hemlock, aspen, or basswood is the safer bet. Ask your doctor if you are unsure.

Hemlock: the value pick for indoor saunas

Canadian hemlock is the workhorse of the infrared sauna market. It is light, even-grained, low in resin, and close to scent-free, which suits people who want a clean, modern look. It costs less than cedar and performs well in a climate-controlled room. It is less naturally rot resistant, so it is a weaker choice for a sauna that sits outside year-round. If you are shopping indoor infrared saunas, hemlock is very common and a sound buy.

Spruce, aspen, and basswood

Nordic spruce

Spruce is the budget classic in Finland. It heats up quickly and smells lightly of pine. Lower grades carry more knots, so pay attention to board grade in kits.

Aspen

Aspen is soft, pale, and has almost no scent or resin. Its big advantage is touch: it stays noticeably cooler than cedar at the same air temperature, which is why many builders use it for benches and backrests even in cedar rooms.

Basswood

Basswood (linden) is the go-to for allergy-conscious buyers. It is odorless, very low in natural oils, and cool to the touch. It is less durable outdoors, so keep it for indoor rooms.

Wood grade matters as much as species

Two saunas built from "cedar" can be very different products. What to check:

• Clear vs knotty. Clear (knot-free) boards look cleaner, and knots can get much hotter than surrounding wood and leak sap. Choose clear for benches and backrests at minimum.
• Kiln-dried. Properly dried wood shrinks and cracks far less once the heater runs.
• Board thickness. Thicker walls and benches hold heat and resist warping. Barrel saunas especially benefit from thick staves.
• No finish inside. Interior walls should be left raw or treated only with a sauna-specific product. Standard stains and varnishes can off-gas when heated.

Which wood should you choose?

Buying an outdoor or barrel sauna in a wet or snowy climate? Choose cedar or thermally modified wood. Browse our outdoor saunas for sale and compare species in the product details.

Putting an infrared cabin in a spare room or basement? Hemlock gives you the best value, and cedar is an upgrade if you want the scent.

Sensitive to smells, dust, or allergens? Pick basswood or aspen, or at least ask for aspen benches.

Want both heat styles? Most hybrid saunas use cedar or hemlock interiors, so the same rules apply.

What to expect in the first week: new cedar smells strongest in the first few sessions, and any wood may release a little sap near knots as it first heats. Wipe it off once cool. Keeping the room ventilated and letting it dry with the door open after each session protects every species.

Sauna wood FAQ

Is cedar or hemlock better for a sauna?

Cedar is better for outdoor saunas and anyone who wants natural rot resistance and the classic scent. Hemlock is better for indoor saunas on a budget and for people who prefer a mild, nearly scent-free room.

Can you use pine or pressure-treated wood in a sauna?

Avoid resin-heavy pine on surfaces you touch and never use pressure-treated lumber inside a sauna. Heat can release resin and treatment chemicals. Stick to sauna-grade softwoods like cedar, hemlock, spruce, aspen, or basswood.

What is the best sauna wood for allergies?

Basswood and aspen are the usual choices because they are low in natural oils and nearly odorless. People with asthma or wood allergies should talk to their doctor before choosing a cedar sauna.