The right wood for sauna construction
The right sauna wood for the sauna. Wood becomes the perfect building material for saunas thanks to its low thermal conductivity. In plain language, this means that the sweat lodges are perfectly insulated. Although the wood stores the heat, burns are almost impossible. So it’s no wonder that the ancient Finns didn’t make the first saunas out of stone. Not all wood is the same. Each has its own unique characteristics when it comes to sauna construction.
Even if the natural raw material for the building of sweat huts is nearly optimal, it brings nevertheless also a few disadvantages with itself: With the merry sweating pleasure it always goes humidly. Just think of the infusion. But even otherwise, moisture builds up in the cozy warmth, causing problems for the wood. Only a few types of wood can withstand this without suffering lasting damage.
But even if these conditions are met, there are some types that resin, splinter or warp. All of this can be highly unpleasant for sauna guests, because no one wants to catch a splinter. To prevent this from happening, make sure you use the right sauna wood. We will introduce you to the seven most important types.
1. Abachi
Abachi wood comes from Africa, more precisely from the area of Nigeria, where it is called “Obeche”. The tree is characterized by the fact that it grows very quickly and thrives even in difficult conditions. Quality and price are largely determined by the exact region of origin. It is decisive for wood quality and finishing.
Abachi is such a good sauna wood because it grows very quickly, conducts heat poorly and thus insulates well. It also has a low tendency to shrink. A particular advantage is that the wood is relatively poor in knots and virtually splinter- and resin-free. It can be used for the entire sauna construction, including benches and doors.
However, there are also a few negative points: For example, the wood is quite soft and thus does not provide a stable hold for either nails or screws. It is also capable of absorbing a lot of moisture. So in poorly ventilated rooms there is a high risk of mold.
It is also important to know that conservation authorities advise against the use of this type of wood. This is because it comes from one of the largest rainforest areas on earth, which is exploited by humans. Nevertheless, it is sold in Germany. It is not currently available on the market as a product with FSC certification. This seal identifies sustainably grown products. A good alternative is the wood of the native poplar.
2. Aspen respectively thermo-aspen
Aspen is a tree that grows quickly and, above all, straight. This also makes it a particularly sustainable raw material. Aspen is ideal as sauna wood because it insulates and also retains its shape. It is often found as a building material for the benches or the reclining surface. The wood has a very light grain and therefore looks very noble as well as high-quality. The raw material has also made a name for itself as an alternative to the well-known hemlock wood.
The aspen is processed in sawmills to so-called thermowood. The name alone promises optimal properties for sauna construction – and this promise is kept: The wood absorbs hardly any moisture and is almost free of resins. If the aspen was treated with heat, microorganisms such as fungi and bacteria cannot harm it either. However, the thermal variant also has a small disadvantage: it appears a little darker than the untreated one. But this is only a visual problem and ultimately a matter of taste.
3. Domestic fir
The good old fir is native to Europe and therefore does not have to travel long distances for transport. A number of species grow in the forests that are well suited as sauna wood. It is stable and therefore durable, has few knots and the resin content is also kept within limits. The wood gives the sauna a lively look because the grains are very different. In the trade, you will mainly encounter the Siberian fir and the European silver fir. They are both perfectly suitable for sauna construction.
When buying, you should definitely pay attention to the origin of the wood. Firs from Northern Europe are usually characterized by higher quality. For example, they are a bit firmer and less resinous than the trees from Southern Europe. If you go for a low-quality wood, you should expect large resin inclusions in particular.
One more thing you should consider when buying: As a rule, you can choose between the domestic and imported species. Similar properties characterize both woods. However, the latter has a much worse ecological balance, because it is transported over many thousands of kilometers. Therefore, reaching for the domestic product makes perfect sense, even if it is a bit more expensive.
4. Hemlock wood
Hemlock wood is well known in Germany. By the way, the name means something like “Hemlock”. The fir is a member of the pine family and thrives particularly well in humid areas, for example, East Asia and North America. Most of the wood from the German trade was harvested in Canada. It is cultivated there on a large scale and can therefore be described as sustainable.
It is so well suited as sauna wood because it is extremely durable, stable, insensitive to moisture and low in resin. In addition, sauna builders are pleased with the light color, which gives the room a noble touch. It is also pleasing that very few branches grow on the Hemlock fir. Branch-free lengths of up to 30 centimeters are not uncommon.
The raw material is mainly used for lining ceilings and walls. But also, interior doors and benches are made of hemlock wood. The light appearance is particularly impressive in combination with glass.
As good as hemlock wood is for sauna construction, there is one thing you should consider before buying: this raw material has to be imported. This makes for a very poor ecological balance. In addition, the long way is sometimes reflected in the price, which affects especially the very good qualities.
5. Kelo wood
The word kelo is Finnish and refers to a very specific way of harvesting wood. Namely, it is dead wood that has been dried in a completely natural way. When it comes to pine, Finns also refer to it as kelohonka, a very common sauna wood.
This type of wood is produced when a tree stops growing because it is too old. It then dries out in the dry and cold climate of Finnish forests. The process of creation is therefore completely natural. To this day, this type of wood cannot be grown by man. That is why it is very rare and, of course, quite expensive. It is so suitable for sauna construction because it is very hard and dimensionally stable. In addition, it can withstand almost any weather conditions. It can be installed completely untreated. You do not have to worry about settlements and cracks.
The Kelo wood that you find in the German trade comes for the most part from Russia, more precisely from the region of Karelia, which is partly even in Finland. Smaller pieces also come directly from Finland or Sweden.
6. Nordic spruce
In the trade, you can also find Nordic spruce, which is used mainly in the outdoor sauna area. The light-colored wood grows quickly, is robust and is characterized by a particularly uniform structure. Its high density provides a high weight, therefore particularly high-quality products can be realized with this raw material.
Spruce has another advantage as sauna wood: it exudes a pleasant scent throughout the room. In addition, the price/performance ratio of this raw material is almost optimal. However, when buying it, you should keep in mind that it is exclusively imported goods, which have a very negative ecological balance.
7. Red cedar
The red cedar is a cedar species from North America. The wood has the color of amber and is quite suitable for sauna construction, because it grows almost knot-free and is very uniformly grained. You will find hardly any resin in cedar, but all the more air: these inclusions provide additional insulation. You hardly need to fear splinters with this high-quality wood. Cedar is very resistant to moisture. A special plus: it contains essential oils, which on the one hand provide a pleasant scent in the sauna. On the other hand, they are able to keep pests away. Therefore, you do not need to protect the wood separately.
However, this raw material is very expensive, because it is extremely high quality and has to travel long distances. By the way, this also provides a very negative ecological balance.
Insufficient wood properties for use in the sauna
These are not the only types of wood that can be used in a sauna, but they are the most common. If you want to use wood from other trees, you must first learn about their properties. Wood species with the following characteristics are not suitable as sauna wood:
- High thermal conductivity
- High moisture absorption
- High resin content
- Poor dimensional stability
- Weak protection against moisture, fungi and pests
- Many knotholes
- Tendency to splinter
You have seen that good sauna wood must have some properties. From this, it follows what kind of wood is not suitable. It must not be soft, must not absorb moisture, moreover, must be able to resist the wetness, be dimensionally stable and insulating.
If you are planning to build a sauna, you should always ask in specialized stores about the particular properties. Also, keep in mind that even among the well-suited varieties, there are big differences in quality. So never go for the cheapest raw material, after all, you want to enjoy your sauna for a long time.
