Basic Principles of Sauna Construction

Start With the Principles | Define Sauna | Consider the Location | Create Heat | Capture the Heat | Include Ample Ventilation | Steam is Essential | Get in the Heat | Get in the Cold | Consider the Space | Baths Have Drains | Make a Place to Chill | Consult the Community | Relax

🧭 Start With the Principles

There are many strong opinions on how to build a sauna “correctly.” And even the experts offer conflicting recommendations. Thankfully, there is more than one way to build a good sauna. If you start by learning the basic principles of sauna construction, they will guide you in the details.

📖 Define Sauna

Contrary to what clever marketers claim, infrared “saunas”, steam rooms, hot tubs, sauna shorts, and many other heat inducing products are NOT sauna. The simplest definition of sauna is, “a Finnish steam bath” — more on that here. But sauna is so much MORE than just a place to sit and sweat. The BATH part is core to its identity.

🏞️ Consider the Location

A sauna set beside a secluded river, lake, or sea is ideal. If you don’t have access to one of those locations, consider building your sauna some distance from your house. It’s less convenient, but creates a sense of separation from daily life. Local zoning laws may also impact your choice of location.

🔥 Create Heat

Sauna enthusiasts often consider wood-burning heaters to be the best, but electric heaters can be great too. Wood-burners allow for more flexibility when selecting remote or outdoor locations, and you have the potential for cheap (even free) fuel. Also, many people love the ritual of creating and tending to their sauna fire. Another thing you will want to consider is the size of your heater in relation to your hot room. For smaller saunas, shielding may be necessary to minimize harsh heat from the stove.

🪨 Capture the Heat

When heating the sauna, the aim is to heat the whole building, which creates a uniform, “smooth” heat. The sauna rocks and wood walls both capture and store heat. And while air temp is the most common measure of sauna readiness, it doesn’t store nearly as much warmth as the rocks and wood — plus hot air is always trying to escape! Trying to contain hot air works against the next principle of ample ventilation. Capturing heat is more important than containing heat.

💨 Include Ample Ventilation

Fresh air is an oft-overlooked element of a pleasant sauna experience. Having ample ventilation makes the heat more enjoyable and results in less fatigue. If you are able to capture lots of heat in your rocks and thick wood walls, planning proper ventilation is a much easier task.

♨ Steam is Essential

Use the stored heat to create steam by splashing water on the rocks. This ingenious hack is what makes sauna so special. The Finnish word for sauna steam is löyly, and löyly is essential.

🥵 Get in the Heat

Hot air and steam rise, so if you want to take advantage of them, you should build your benches near the ceiling. If space permits, build your sauna hot room taller than eight feet. This creates more space for the steam/heat pocket at the ceiling.

🥶 Get in the Cold

When cold water is coupled with the heat of sauna, it creates an experience that is better than the sum of its parts. A plunge in a lake or stock tank is the best way to experience a deep, all-encompassing cold.

🏰 Consider the Space

If you like your friends and enjoy hosting, build a large sauna hot room. If you don’t, keep it small and secret. We love to sauna with friends, so our hot room is big. You’ll also need to give thought to windows, lighting, flow of traffic, changing room, and bench style. There’s no one right answer, so research different options.

🛁 Baths Have Drains

Historically, sauna is a bath. And many traditional saunas have showers or hot water tanks that are used for bathing. Also, don’t be shy when splashing water on yourself and the rocks.

😌 Make a Place to Chill

Comfortable chairs, good lighting, and shelter make relaxing between rounds more pleasant.

💻 Consult the Community

There are many great online sauna forums. The members, though sometimes cantankerous, can provide helpful information. Consult them, but always subject their advice to careful scrutiny. A few online sauna communities are: Reddit, Sauna Design, Wood-fired sauna, Wood-burning sauna. If you are looking for more “official” guidance, I recommend these books: Sauna The Finnish Bath (Viherjuuri), The Modern Sauna (Konya), Secrets of Finnish Sauna Design (Liikkanen), The Art of Sauna Building (Jalasjaa). And Saunologia, and Trumpkin’s Notes are some websites worth checking out. But remember, even advice from expert sources should be carefully scrutinized.

😌 Relax

Remember, the key is to let the sauna construction principles guide you rather than relying on prescriptions from experts. If you take the time to understand how heat stratification, steam “pockets”, soft vs. intense heat, and ventilation all affect the sauna experience, you will be able to make informed decisions and informed compromises; almost all sauna builds will require some compromises. You don’t have to be a pro to build a great sauna. And remember to relax; you‘ll do great!