Choosing the right wood for your sauna is not just about the aesthetic appeal; it also greatly influences the durability and the sauna experience. The selection criteria hinge on the wood’s ability to resist heat and moisture without releasing resin or overheating.
These are the best types of wood suitable for sauna walls, their unique properties, and why they matter.
Selecting the Perfect Wood: An Array of Choices
#1 Common Aspen (Populus tremula)
Common Aspen is often the first choice for sauna interiors and exteriors, thanks to its light tone, smooth texture, and its trait of not secreting resin. This wood type is distinctive for its rich colorfulness and low density, though it does exhibit knots that add to its rustic appeal. Just be mindful of where these knots are placed during installation, especially where sitting is expected.
One aspect to be aware of is Aspen’s tendency to shrink more than other wood types. However, this is not a problem if accounted for during the installation process. Aspen benches are indeed an attractive choice for your next sauna build.
Aspen tends to be more expensive than other popular sauna woods, but many find the extra cost worthwhile for its unique benefits.
Another benefit of Aspen is its durability over time. Aspen retains its original look even after five years without sanding or finishing. This makes Aspen a low-maintenance option for saunas. It’s worth noting that Aspen turns grey over time, but this doesn’t affect its structural integrity or usability. If this aesthetic change is undesirable, periodic maintenance such as sanding and sealing can help retain its original color.
On the other hand, Aspen doesn’t react well to water. Over time, exposure to moisture can cause it to grey and mold. The risk of water damage can be significantly reduced with careful installation and measures like using a drip edge.
In crowded commercial spaces, Aspen has proven to age better than cedar. Given the lower traffic in a residential setting, Aspen will likely maintain its appeal for longer. Regular maintenance, such as an annual sanding and sealer application, can help ensure its longevity and continued attractiveness.
In Scandinavia, Aspen is almost the standard for saunas and is the preferred choice in places like Estonia. This is likely due to the wood’s many benefits, including its smooth texture, light tone, and the fact that it doesn’t secrete resin, which could otherwise cause discomfort in a sauna setting.
In summary, Aspen is a fantastic choice for sauna interiors and exteriors. Its smooth texture, light tone, non-resinous nature, and longevity make it well worth the investment. While it may require some maintenance to prevent greying and water damage, these efforts are minor compared to the benefits of this beautiful, durable wood.
Each downside of aspen in saunas can be solved by opting for thermally treated aspen (more below).
You can see regular and thermally modified aspen in action in Auroom sauna kits.
#2 Alder (Alnus glutinosa)
Alder is an excellent choice for sauna interiors and exteriors due to its inherent resilience, pleasant texture, and remarkable water-repellent properties. Native to regions spanning Europe, southwestern Asia, and northern Africa, the common Alder, or black Alder, has become popular as a sauna material. Whether thermally modified or used in its natural form, Alder stands out with a lovely reddish hue that enhances the visual warmth of any sauna.
One of the striking features of Alder is its hardiness, making it a particularly robust choice for environments with frequent temperature fluctuations, such as saunas. This strength does not compromise its texture, which remains pleasant, making it comfortable for use in seating or flooring. Alder does not overheat, making it a safer choice for high-temperature environments.
Another notable characteristic of Alder is its water-repellence. Saunas, by nature, are high-humidity environments, and the material used in their construction needs to withstand this moisture. Alder excels in this regard, holding up well against moisture and steam without compromising its structural integrity or aesthetics. This makes Alder durable, maintaining its form and function over time.
The visual appeal of Alder is another compelling factor for its use in saunas. Its reddish tone provides a warm, inviting aesthetic that enriches the sauna experience. This natural hue complements a sauna’s relaxing and rejuvenating environment and adds to its rustic charm.
Alder wood is also versatile in its finish options. It can be thermally modified for improved durability and stability or used in its natural state, showcasing its innate beauty. Both options offer their unique benefits, and the choice between them would depend on individual preferences and specific sauna requirements.
Alder is a fantastic choice for sauna use. Its hardiness, pleasant texture, water resistance, and the beauty of its reddish hue make it an excellent choice for those seeking a durable, attractive, and functional sauna material. Whether you’re looking for a thermally modified wood with enhanced properties or untreated Alder’s natural charm and robustness, this wood is a sound investment for any sauna project.
You can buy alder sauna wood from us at SaunaMarketplace.com. We sell a variety of dimensional lumber and profiles like 1×4 tongue and groove, modern vertical step cladding, and various bench and backrest sizes. Alder is also available on several Auroom Saunas for sale here.
#3 Thermally Modified Norway Spruce (Picea abies)
When looking for a unique, durable, and visually appealing wood for your sauna that can handle the outdoors, thermally modified Norway Spruce is a standout choice. Available through Sauna Marketplace in barrel sauna kits, 1×4 T&G, and 2×4 material – it’s a favorite among customers for its many attributes.
Thermally modified Norway Spruce rustic appearance and visible knots bring a sense of natural serenity to your sauna. The wood undergoes a thermal modification process from Thermoy, which enhances its weather resistance and durability. This process also gives the wood a naturally beautiful light-golden tone, adding to its aesthetic appeal.
This type of wood is an environmentally friendly choice. It is derived from sustainable forests, with no chemicals involved in its modification process. The thermal modification provides the spruce with excellent durability (class 1), offering 25+ years of protection against wood decay. The process also significantly reduces the wood’s moisture absorption capability and rate, resulting in less moisture-induced deformation.
The Norway Spruce is light in weight, soft, and presents a nearly white color in its untreated state. It boasts medium mechanical properties and splits less easily than pine due to being less resinous. It becomes considerably more durable and stable after thermal modification while taking on a beautiful golden-brown tone.
Thermally modified Norway Spruce is an excellent choice for sauna wall cladding, providing a beautiful, durable, and environmentally friendly solution for enthusiasts. You can find this exceptional wood material in the barrel sauna kits offered by Sauna Marketplace, and customers have reported high levels of satisfaction with their purchase.
You can also contact us for 1×4 T&G or 2×4″ dimensional sauna wood.
Western Red Cedar (Thuja plicata)
Western Red Cedar is loved for its water-repellency, delightful aroma, and ability to resist overheating, making it a charming choice for sauna walls. When North Americans think of saunas, they think of this wood type and that’s not changing anytime soon.
Cedar is widely popular in the U.S. and Canada, but European countries such as Finland and Sweden rarely use it in saunas. That’s mostly because they don’t know what this North American timber is, but also due to its potent aroma. Moreover, cedar contains Thujone, which can be a neurotoxin and a potential carcinogen. Despite its charm, its usage should be considered with caution.
If you’ve been in a gym or hotel sauna, you know cedar doesn’t always age well.
Canadian Hemlock (Tsuga canadensis)
Canadian Hemlock stands out due to its durability, knot-free texture, and ability to radiate heat evenly, making it an excellent choice for sauna interiors.
Other choices include the Common Alder, Scots Pine, Norway Spruce, American Ash, Radiata Pine, Poplar, and Magnolia. Each offers unique properties that can suit various aspects of sauna interiors or exteriors.
Why Wood Matters: More Than Just Aesthetics
Apart from giving your sauna a great look, wood has functional benefits. It possesses hygroscopic properties, which can absorb humidity and then release heat, leading to a comfortable sauna experience. Some woods, like Abachi, have the advantage of staying cooler to the touch and absorbing noise, thus creating a peaceful ambiance.
The functionality of wood increases with height. Therefore, using more wood in the upper sections of the sauna is recommended. If you’re considering including aesthetic elements like exposed brick, try to place them in the lower portions, keeping the upper three-quarters all wood.
Tips for Installation: Board Size and T&G Construction
Regarding the board size for interior cladding, a 1” x 4” nominal size is usually considered optimal. However, you can go for wider or thinner boards, considering that they might cup in colder climates.
You can’t overlook the use of Tongue & Groove (T&G) construction. Given a sauna’s extreme temperature and moisture conditions, wood may warp. The T&G construction can help reduce this effect. If you opt for T&G, install it with the groove facing down to prevent sweat or moisture from collecting in the grooves.
Choosing the right wood for your sauna is critical to its aesthetic appeal and functionality. Thus, it’s imperative to understand the properties of each wood type and select the one that best fits your sauna needs and preferences. Contact us for a full catalog of sauna wood types available in dimensional lumber, prebuilt saunas, sauna kits, and from custom builders.