Garden sauna room project requirements
The brief for this project was to build a fully functioning outdoor sauna in the clients’ garden. The clients requested that their new garden sauna be designed to look unique and unusual, with a rustic, woodland aesthetic. The founder of Treegarden, Chris Hore, is a wood sculptor and Master Craftsman who specialises in traditional, rustic woodcrafting techniques. Needless to say, this project suited Treegarden to a tee!
(If you like you can skip the article and go straight to the captioned photo gallery.)
The new garden sauna was to be located in an unused, overgrown corner of the garden. We conceived an innovative triangular design, with two straight sides at ninety degrees and a curved front. The straight sides would fit neatly into the corner of the garden. This design uses precious garden space efficiently and allows the curved front of the sauna to face outward across the garden.
Having seen the photos from our Brighton shed with green roof project, the clients requested a similar roof. A green roof can provide greater insulation benefits than a standard roof. This is important in a garden sauna, which is required to maintain significant heat as efficiently as possible.
A green roof also provides a place to plant grass and wild flowers, bringing colour and life to the garden sauna structure. After a few months of growth, the sauna room would start to bed in and become part of its natural surroundings.
Since this was an outdoor sauna, it would need to be waterproofed with a cladding of some description, and this cladding would need to fit the rustic look and feel requested in the brief. It would also need to follow and compliment the curved front of the sauna, which also required a door opening. To complete the desired aesthetic we designed a round, hobbit-style door for our garden sauna room.
Building the garden sauna room
To start the build, we cemented eleven upright timber posts into the ground. We then built a floor framework from timber, fixed to the upright posts at around four inches above ground level.
Before boarding the floor with plywood, we decided it was best to get a roof on the structure and waterproof it. We built a framework for the roof with timber joists, ensuring it had a slope from the back corner to the front. This slope allows excess water from rainfall to drain from the completed green roof, ensuring it doesn’t become too waterlogged.
We then boarded the roof with marine ply, which is the favoured material for boat decking and other outdoor projects. We covered the marine ply with a layer of standard roofing felt, stuck down with bitumen roof felt adhesive. To ensure that the roof would not leak, we sealed the seams between the strips of felt with bitumen paint.
With the roof adequately waterproofed for the time being, we were able to board the floor and external walls of the garden sauna, also with marine ply. Marine ply is flexible enough that we could fasten it to the framework in a curved shape around the front face of the sauna structure.
We cut rolls of high quality insulating fleece to the required sizes, then stuffed it into the cavities between the framework and the eternal wall paneling. We then did the same with the floor and ceiling cavities. That allowed us to panel the wall, floor and ceiling interiors, which we did using attractive tongue-and-groove pine cladding.
It was then necessary to incorporate two air vents into the walls of the garden sauna. The vents can be opened and closed manually, allowing fresh air into the sauna room should it become undesirably hot during use. The vents also allow the user to air out the sauna after use.
The next task was to create a round, hobbit-style door to allow the user access to the garden sauna room. This was no easy task; the door opening is designed into the curved front face of the sauna, meaning that the door had to be round and curved. However, we achieved this and then finished it off with a round, port-hole style window.
We then clad the garden sauna walls with the type of feathered boards usually used for fencing. To really express the curve of the sauna’s front face, we set the boards at a forty-five degree angle. The idea was to create a top-to-bottom ‘wave’ effect, which we achieved by setting the feather boards at different heights from the surface of the sauna wall.
The next job was to finish the green roof, which still required additional waterproofing. We used a sheet of Butyl rubber roof liner, with a layer of Butyl Geotextile Liner Protection underneath it to save the roof liner from tears. We were then able to add the soil and growing medium, allowing the clients to start planting vegetation. (For more information on how to build green roofs, see our article Garden shed with green roof in Brighton.)
To give the exterior of the garden sauna a more natural, rustic appearance, we finished the front edge of the roof with off-cuts of bark-covered oak.
The exterior of the garden sauna was almost complete, but a few additional features were still required. The clients intended to use the sauna to relax in the evenings, so we fitted a pair of electric lamps above the door on either side.
Also, the need to build the floor framework several inches above ground level meant that two steps were required for easy access to the garden sauna entrance. We used oak boards for the steps, and fronted them with bark-covered oak for a more rustic feel. Chris then finished this off by creating hand rails on either side of the steps, using natural ash limbs for an organic, twisted appearance.
Finally, we built planters around the curved front face of the garden sauna. A timber frame created the curve, and we fronted the planters with off-cuts of bark-covered oak. The planters add to the organic look of the sauna exterior, and will help it to bed into its surroundings over time. When filled with soil, they will also provide the sauna with additional heat insulation during use.
The garden sauna room interior
With the exterior of our garden sauna complete, we turned our attention to the interior furnishings. We built a curved pinewood bench into the corner of the room, along the two straight sides, and then built another above it. The lower bench brings you closer to the heat, whilst the upper bench is a little cooler.
We then added a single light which we diffused with a slatted cover to provide a soft, relaxing light when using the sauna.
The final job was to ensure that the sauna was supplied with enough power to generate the required heat for a sauna. Since the user needed the ability to regulate the heat themselves, we chose an adjustable variable-temperature control unit. Power to the garden sauna is supplied from the main fuse box of the client’s house. A consumer unit, housed on the sauna exterior, connects power to the lights and the sauna heater, both of which are on independent circuit breakers.
Garden sauna project gallery
Check out the photo gallery, showing the project from start to finish. If you are looking for a local business to help with a garden project of any kind, please contact us to discuss your requirements.