Things to think about before and during...
Location - Assess your plot to best position your sauna. Maybe you already have the perfect view, but if you don’t, then you can consider elevating your sauna using a platform or decked area.
Floor drain - Always have a floor drain in the wood-burning sauna and preferably also in the electric sauna. You will also need to consider how you will source water to throw on the stones.
Placement of the heater - The size of the sauna, whether you are going to include glass panels and what insulation you use will determine how effective your sauna heater is. Keep in mind minimum safety distances when planning where in the sauna the heater should stand. Different heaters can have different safety distances to combustible materials, so check the building regulations carefully when planning.
When using a wood burning heater, you should also plan where you will place the chimney. It is most common to take the chimney straight up through the sauna roof, backwards out through the wall or to connect to a masonry chimney.
Ventilation - There are different suggestions for heaters, but a standard procedure is that air comes from below the heater and exits diagonally across the room. Read more here. If you have a wood burner it is particularly important to have an air supply to assist the burning of the wood.
Construction - It is essential to follow building regulations – ask your material dealer for advice and there are also some helpful web-pages. A good tip is that if you are going to use a heavy heater, with lots of rock, it would be advisable to use extra support directly beneath it.
Exterior walls - There are lots of choices when it comes to the sauna’s exterior. Some use a cottage-style wooden façade while others are constructed with bricks or plastered walls to match the customer’s home and surrounding buildings. It is important to plan the air inlet and extraction properly prior to construction as this is difficult to rectify later.
Insulation - It is preferable to use mineral-based wool in the walls and ceiling. There is insulation made of polyurethane foam that also works well. Do not use expanded polystyrene (Styrofoam). This theoretically withstands 80-degree temperatures but in reality crumbles within the walls.
Sauna panels - There are a large variety of wood finishes that work well in sauna. Spruce, Aspen and Alder are most commonly used as they handle heat and moisture well. Panels can be mounted vertically or horizontally according to taste.
Floor - Saunas do not come with a floor. They sit upon a pre-laid flooring of your choice. Tiles work very well as a neat base which can be easily cleaned. Plastic mats can be used which are then sealed at least 10 cm up the sauna walls. Another option is a fiberglass mat with polyester which can have a coloured top coat applied. Finally, concrete floors are fine but can feel a little cold underfoot in which case wooden duckboards can be laid on top for walking on.
Glass - The use of glass in outdoor sauna can enhance natural light and help the feeling of being closer to nature. Opening windows are useful to quickly clear the air between sauna sessions. Full glass panels, where there is a risk a bather could lean on them, should always be made with tempered safety glass.
This also applies to windows which are directly adjacent to the heater. All other windows can use standard glass but always consider that the more glass you use the more power you will need from the heater and you may need to size up.
Surface treatment - Different types of wood should be treated differently so make sure you consider this when buying sauna benches and other interior items. If wood treatment is needed, it is important this is done before using the sauna.
Things to think about afterwards
Absolutely nothing. Just enjoy!