blog

In the Checklist for building a sauna article, you will find tips on things to consider when you are building or buying a sauna.

The article was inspired by a Finnish expat friend’s thoughts on what to consider when starting to build your own sauna. So here now I have listed a few things that came to mind. Please drop me a comment if you missed something important.

Checklist for building a sauna

Where to build a sauna

The first thing to think about is where to build your sauna. Whether it makes more sense to build a sauna in the yard or inside the house. Is there room for a sauna on the ground floor, is it possible to build a sauna in the basement or in the attic?

What kind of sauna

The next thing to think about is what kind of sauna is best for you. Is it a garden sauna, a turnkey sauna, a bathroom sauna? Will you build or have the sauna built entirely by yourself?

What kind of heater?

Which heater is best for your needs, whether it’s wood-burning or electric. The size of your sauna and whether it has a window, for example, will determine how big or efficient a stove you should buy for your sauna. The number of people using the sauna should also be taken into account. Plus how often you sauna.

To get a wood stove I need a chimney and permits from a chimney sweep. Living abroad, this can be a bit difficult, but I’m sure it will work out in the end.

Who builds the sauna?

Next, it’s a good idea to think about who will build/operate the sauna. Are you handy with your hands or is there someone in your family circle of acquaintances who can help? Will you build the sauna from “long wood” or is it sensible to order a prefabricated sauna?

Wood materials

Which wood material to choose for sauna structures, panels and ceilings. There are many options and so-called colours. It is worth taking some time to think about which woods are suitable for your sauna.

Pine or spruce are usually used for sauna structures.

For the boards, it is advisable to use heat-treated wood. In Finland, spruce, alder or aspen and apache are used because they do not conduct heat well.

Panels can be untreated wood. However, wall and ceiling panels should be treated with sauna protection after installation.

Ventilation

The importance of ventilation cannot be ignored. Especially here in Germany, you see an annoying number of saunas with no ventilation at all.

Make sure that your Finnish sauna has either pressurised or mechanical ventilation. In saunas with wood-burning stoves, the ventilation is set up so that the supply air comes from the bottom and the exhaust air exits from the top.

Sealing and insulating the sauna

Sealing the sauna is particularly useful when the sauna is built in a residential building. Seals prevent the spread of moisture to the rest of the house.

It is worth insulating the sauna to prevent heat escaping. It is advisable to put 20 cm of insulation in the ceiling and 10 cm in the walls. Insulation is particularly important when building a garden sauna, especially if the sauna is used in winter.

The sauna heats up faster.

Flooring materials

The flooring material in saunas is nowadays tile. Remember that waterproofing is required and that the tiles are also raised slightly on the wall by 15-20 cm. From which the panels will then rise.

Sauna ceilings

Sauna ceilings are also calculated according to a certain formula, for example 60 cm width per person.

The difference in height between the top ceiling and the ceiling is 100-100 cm.

The total depth of the boards should be 100-120 cm and the width of the seating board should be 60-80 cm. The footrest should be 40 cm wide and should ideally be positioned at the height of the stove stones.

Floor drain

Make sure you have thought about the location of the floor drains. It would be best if the sauna and the washroom have their own floor drains. But of course that is not always possible.

Electricity

For the sauna you will also need electricity for lights and e.g. for the electric stove. The junction boxes required for the electrical connection are provided near the electric stove and the group wiring is brought to the boxes. The installation box should be placed 3 cm above the floor on the side of the heater. The piping is included in the cold side of the heat insulation when the sauna is installed.

Here are some things that came to mind when you think about what to consider when you start building a sauna. Drop me a comment if I missed something important.

Checklist for building a sauna

Where to build a sauna
What kind of sauna
What kind of heater
Who builds the sauna
Wood materials
Ventilation
Sealing and insulating your sauna
Flooring materials
Sauna ceilings
Floor well
Electricity

In this Checklist for building a sauna article, I have put down the things I thought you should know when building a sauna in Finland or abroad.

However, you should contact a professional if you are unsure about anything or have any further questions.

With love,

Sauna-Kati

The article “What is the best firewood to burn in a sauna” presents the most commonly used firewood in Finland.

Which wood gives the most heat?

Which wood produces the most soot?

All these questions are answered in this article.

What is the best firewood to burn in a sauna

You should only choose dry logs for your sauna heater. But which is the best firewood? I don’t think there is just one answer to this question.

You should never use wet wood, so-called waste wood, i.e. painted or varnished wood or other waste, in a sauna heater.

Fresh wood normally has a moisture content of 40-60%. The moisture content is influenced by the location, the type of wood and the age of the wood. The moisture content also varies in different parts of the wood. The moisture content of hardwood also depends on the seasons.

Logs should have a moisture content of 15-20%. This is usually achieved by drying for 4-6 months.

You can also speak of overaged firewood that has been dried for two summers.

Wie zündet man eine Holzsauna richtig an

What is the best firewood to burn in a sauna?

Birch

In Finland, the prevailing opinion is that birch is the best firewood. However, this is not necessarily the case. Birch is the best and densest wood in terms of calorific value. Birch wood also smells wonderful when it burns. However, birch soots more in the stove and chimney. This can lead to a soot fire in the long term.

This is why you should burn other types of wood with birch. Mixed wood keeps the stove and chimney “clean”.

At the moment, firewood dealers have increased the price of birch logs. It is therefore not a bad idea to burn other wood from time to time.

Pine

Pine is a slightly softer wood than birch and burns faster than birch.
But it is very suitable as firewood. However, it should be noted that pine leaves more ash and the stove needs to be cleaned more often.

Pine resin can also cause a certain amount of crackling, but not as much as when burning spruce. Pine burns well, is readily available and cheaper than birch.

Spruce

Spruce has a slightly lower density than pine. Spruce resin can cause crackling and flying sparks in the firebox. The ash can also contaminate the stove. Spruce wood is easy to ignite.

However, according to the KIUAS study, spruce is the most environmentally friendly.

One advantage of conifers is that they dry out more quickly than birch or aspen, for example.

Alder

Alder burns in the oven with a large flame and gives a good, “soft” fire. Alder wood chips are also used for smoking and give fish, for example, a great aroma.

Aspen

Aspen is not a well-known firewood, but can be used as a good kindling. It ignites well compared to other firewoods. Aspen can also have a slight crackling effect. Aspen needs just as much time to dry as birch.

Which wood provides the most heat?

According to studies, in this order

Birch
Pine
Spruce
Alder
Aspen

Which wood produces the most soot?

According to a study by the KIUAS project at the University of Eastern Finland, pine has the highest soot content and spruce the lowest.

The highest concentration of particulate matter was found in alder and birch with bark. The lowest in spruce.

The carbon monoxide concentration was highest in alder with bark and lowest in pine.

The highest nitrogen oxide concentration was found in alder.

In terms of emissions, nitrogen oxide concentrations were 13-30 % lower in unbarked trees. Soot concentrations, however, were higher in unpeeled trees.

They were 30 and 40 % higher for birch and alder respectively. In the case of PM1 concentrations, only alder was affected, with the values for unpeeled trees being up to half as low as for peeled trees. PM1=particles with an aerodynamic particle size of less than 1µm.

Why should wet wood not be burned?

When burning wet wood, the water must first evaporate and only then can the wood generate heat energy. In other words, the more water the wood contains, the less heat is generated.

Burning wet wood also significantly increases the amount of harmful emissions.

You can find out more about the effects of different types of wood on emissions in the KIUAS project at the University of Eastern Finland.

Why shouldn’t waste be burned in the sauna heater?

Brown corrugated cardboard and milk cartons increase the number of dirt particles many times over compared to burning clean wood.

Carbon dioxide and nitrous oxide emissions and their fluctuations were also higher.

Cardboard and milk cartons produce large amounts of ash in the stove, which affects emissions over longer periods of time.

What size firewood is good?

The length of the firewood should match the length of the grate, in most stoves 25-35 cm long. The diameter of a log is about 10 cm, i.e. at most the thickness of a man’s wrist.

At the beginning you should burn smaller logs, later you can add slightly thicker logs.

Of course, there are also other woods that can be burned, such as oak, beech and ash, which are more expensive as precious woods and take longer to dry. If you have fallen trees in your garden, you can of course also burn them as long as they are stored and dry.

To summarize, it is advisable to burn mixed wood in the sauna heater. Each type of wood has its own characteristics and advantages.

In addition, it is important to keep the stove in good condition and to check that everything is in order in the firebox and chimney.

Have a good time in the sauna!

With love,

Sauna-Kati