When to build a Finnish sauna on a plot of land? At what time of the year?


Building a sauna is a serious project that requires careful planning. One important decision is the choice of season for construction. It would seem to be an insignificant factor, but in fact the choice of season can significantly affect the construction process and future use of the sauna. In this article, we will discuss which time of year is best for building a sauna and what factors to consider when choosing the time.

Features of sauna construction in different seasons


Building a sauna in the summer has its pros and cons, which should be taken into account when deciding when to start construction work.


  • Favorable weather conditions: It is warmer and drier in summer, which is favorable for construction work. There is no need to worry about rain, snow or frost, making the construction process easier.
  • Availability of materials: There is a greater choice of construction materials in the summer, and their price is often lower than in the winter season. It is also possible to get the right tools and construction equipment more easily.
  • Garden and landscape: In the summer, it can be more enjoyable to work outdoors and in the beautiful surroundings of the garden, which promotes motivation to work and makes building a sauna more comfortable.


  • Impact on wood: Weather fluctuations are more noticeable in summer; wood is negatively affected by rain and sun. If wood was harvested in winter, it will become damp and swollen if not harvested before warming.
  • Summer wood (as opposed to winter wood) is more susceptible to fungi, insects and harmful microorganisms because it contains more moisture than winter wood.
  • Overpriced services and materials: Both the materials themselves and the services of construction companies are more expensive. In summer, craftsmen have more work to do, so there’s a chance they’ll rush to complete an order. This is not the case in winter, as the construction rush is quite low and companies stick to each order.
  • High temperatures: During hot weather, it can be difficult to work on a construction site due to high temperatures, which can negatively affect productivity. In summer, the days are longer, forcing you to work during the day, which can lead to fatigue and weakness.
  • Increased corrosion: Due to the humidity that often occurs in the summer, materials can corrode and deteriorate faster.


At first glance, building a sauna in winter may seem like the worst idea, since it’s cold outside and the daylight hours are short. I don’t know if this will surprise you, but the best time to build a sauna is actually winter! We’ll tell you why.


  • In winter, the tree hardly grows, which allows the wood to be low in starch and moisture, as well as to kill bacteria, bugs and pests. Wood cut in winter is more durable and long-lasting.
  • A sauna built with winter wood is less prone to cracking and defects, due to less shrinkage of the wood in winter and better control of wood moisture.
    Winter wood is less susceptible to disease and does not require special protection, unlike wood harvested in warmer seasons, where humidity promotes the development of wood diseases.
  • There are usually no queues in winter, and construction companies organize promotions and discounts for their customers. In addition, construction deadlines are shortened compared to summer, as the main work of designing, manufacturing and erecting the building is much faster.
  • If you build your sauna in winter, you can finish the finishing work as early as mid-summer and start using the sauna. If you build in summer, you won’t be able to finish it in the same season, unless you want a building with cracks and sagging walls.
  • If you have a vegetable garden near the sauna, winter will protect the soil from damage caused by construction machinery, as the ground will be harder.

It is best to use winter lumber to build a sauna


  • In very cold weather, it becomes impossible to make cuts or saws in wood, as the wood begins to crumble in the cold.
  • In winter, the working day is much shorter. And working conditions are less comfortable.
  • High costs of heating the work area.
  • Risk of injury when working on icy or slippery surfaces, as construction work may involve working on a roof or ladder.

It is not advisable to work with wood during periods of excessive frost, as it then becomes too brittle and dry. The most suitable temperature is -10-15 °C, and the maximum temperature allowed for construction is 25 °C.

Spring and autumn

Building a sauna in spring and autumn has its drawbacks. During this period, water evaporates intensively from the wood, which leads to the formation of cracks on the material. In addition, wood harvested in autumn, summer and spring is prone to mold growth, even though it is coated with an anti-mold agent during transportation. However, it cannot be guaranteed to completely destroy all mold.

In autumn, it is best to do preparatory work on the site, such as leveling the ground and making a foundation for the sauna.

In the spring, when you have the sauna’s frame and roof built, you can proceed with the installation of insulation and insulating, finishing work and the installation of lighting and ventilation.

Decided: better to build a sauna in winter

The best time to build a sauna is in winter. Construction can also be carried out in the summer, but in that case the structure should be left until next spring. Then the finishing and other necessary work is done.

If you summarize the above, you can make a small “seasonal” plan for the optimal construction of a wooden sauna:

  1. Late autumn is the best time to build the foundation;
  2. Winter – This is the time to purchase the wood and build the sauna frame;
  3. Spring – After allowing a minimum of three months for the wood to shrink, you can start finishing the sauna;
  4. Summer – Completion of internal finishing work and time to enjoy the sauna in comfort.

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Since 2011 I have had my own business selling sauna building materials, sauna cookers and sauna accessories. I know all about building a quality sauna!