Sweat it out in your very own authentic Finnish garden sauna

Lockdown in the UK has given everyone lucky enough to have an outdoor space the opportunity to enjoy them at home and the outdoor wellness and garden DIY markets are booming. Following this trend, the sauna industry has experienced a growing interest in garden saunas. An outdoor sauna allows you to enjoy your garden at more times of the day and year. When you’ve been bathing at 90 degrees C, you won’t care if it’s dark, below zero or even snowing outside. A space to cool off and relax on loungers or other seating between bathing intervals is a great idea and an even better one is the addition of either a cold plunge pool or cold shower. Both will provide a huge endorphin rush.

Robbie Thompson works for authentic Finnish sauna specialists Finnmark Sauna. He told us, “We’ve seen a surge in interest in garden saunas as people build their own home gym and spa areas with the closure of gyms and leisure clubs. Finnish saunas provide many physical and mental health benefits and the Finnish art of “löyly”,(mainly to do with the steam that evaporates from the heater stones when pouring water on them) connects people with nature. It’s a crucial aspect of the authentic sauna experience and one of the factors which differentiate them from infrared variants.”

Rustic log saunas are still the most common outdoor saunas in Finland but the demand for smaller garden saunas continues to grow in the country and as the sauna industry keeps developing there are multiple unique options to suit different types of outdoor spaces. Helpfully, UK gardens and outdoor spaces can usually be easily adapted to accommodate Finnish saunas. To do it right there are some key rules to adhere to. They’ll all make sure you aren’t disappointed with the end result and mean you’ll be able to enjoy authentic Finnish sauna sessions for years to come.

Keen on a sauna cabin? Work out if the cabin build would be accepted as permitted development in your area. check the planning portal regarding outbuildings and find out whether the size and location of your cabin will require planning permission. Also, does the cabin need electricity, water or drainage? It will help sway where you consider putting the cabin if any of these answers are yes. When it comes to sauna heater choice think about the frequency of its use, and convenience. Some smoke controlled zones like cities may steer you towards an electrically heated sauna. When considering what foundations to build on it depends on what solution you go for. Modular sauna kit cabins usually have a timber base on them and the foundation will depend on what the base is made of. They may require piles to keep them clear of the ground so that the base doesn’t have permanent contact with the ground. Ground screws can be a quick and low-cost option.

It’s absolutely crucial to ensure that you specify your cabin to allow all the bathers to sit above the top of the heater in a room with a flat ceiling or one that doesn’t create an atmosphere where all the heat and steam sits up too high in the room. For best results, factor roughly 600mm x 600mm of bench space for every bather you want to accommodate. Consider specifying the top bench being long enough for someone to lie down flat too and do take into account that the heater and its safety clearances may require a large proportion of your available space. Do also make sure your heater has sufficient power to heat the computational volume of your sauna it will include the loss factor of any glazing and uninsulated walls/ceiling.

If space is limited, then you may need to go for an outdoor bespoke sauna installation rather than a cabin or modular cabin kit. It allows you to maximise the available internal space rather than relying on finding or adapting something to fit.

Do be aware that an electric sauna heater will probably need a significant cable running from your incoming supply or mainboard/consumer unit inside your house and make sure your house has enough electricity capacity. For example, if you have a 100amp supply to your house and you also have an electric cooker, a power shower and a 9kW sauna heater, then you could overload your supply if all were on concurrently. You may need to safeguard your supply by ensuring multiple appliances cannot be on at the same time by means of priority switching with contactors. With wood-burning stoves, it’s not just the heater you need to consider because you’ll need a flue kit and think about heat shielding and installation.

When it comes to your choice of wood, thermal treatment makes them much more stable. Take aspen, for example, it keeps its low-density benefits with the addition of a lovely dark, richer colour and toasted aroma from the thermal treatment process. Treating the external timber also helps maintain the colour and prevents mould, mildew, algae and rot. Treating all interior timbers with white mineral oil or paraffin oil on both sides helps seal the wood. If you are practical and get all the materials to build one yourself to build a small, simple authentic Finnish sauna you could get it all done for around £5000 worth of materials. Bespoke installations which take into consideration design time and installation experts will be more expensive.