In this post I will take you through an outdoor sauna build, covering some frequently asked questions, technical considerations and a few issues we have come across and things we have done to address them. I will try to work through the build in a few sections, (location/placement, materials/structure, maintenance and care).
There are two lenses to look at sauna placement through, aesthetic appeal and installation requirements. On one hand you will want the sauna to be a neat focal point in your yard and you will want to situate it so you will have the best views from the inside out. On the other hand you will have to balance out the technical requirements. You will need to eliminate unnecessary distance for electrical hookups (unless you are installing a woodburning stove or cost is not a factor). You will want a relatively flat area and also solid ground to eliminate shifting and settling or you may need to consider frost footings or a concrete slab. In most cases we follow a similar installation process to a prefab shed. We will set landscape blocks in the corners to set the base on and in some cases install fabric and mulch or rock underneath the deck.
One of the major improvements we have made early on in our sauna building venture is to go all in on the structural components for the floor/deck system. Ground contact treated framing would be a standard approach. We have found that even though treated materials may withstand rot and maintain their load strength for many years or even the life of the structure, they are subject and even apt to warping and cupping quickly and it is difficult to trim the exterior with a cedar board without large gaps appearing at he joints or changes in the floor board. This is not specific to an outdoor sauna and there are years and years of proof of these issues in cedar decks.
In an attempt to adapt and overcome we ended up with a solution that includes fabricated steel joists for strength and stiffness that have been powdercoated for longevity. We coupled these joists with a cedar timber for the frame. This timber will cover the strength and finished appeal aspects with one board instead of two. Simplicity for the win.
The rest of the build I will cover quickly with a few notable items in an effort to limit rambling.
First, glass/glazing/windows etc. What we have found in this department is that professionals in this industry have put in the time, effort and research to make our decision making simple. You will want glass that is safe and glass that has good insulating qualities. We want to keep heat in and we don't want injuries so we decided on a 3/4" double pane tempered glass. For future builds there are a few things aesthetically to play with (one way mirrored glass, tint etc) but for now the basics are safety and insulation.
The rest of the build is subject to budget and architectural appeal. The options are almost literally endless. Steel style and color can be an overwhelming choice to tackle in itself and you haven't even considered wall and floor cladding or light fixtures and heaters. Aspen, Cedar, Basswood, and Spruce are all common options for saunas and there is no need to limit yourself to just one (two-tone may be your style)! As for stoves sizing is important but straight forward and after that its all about style and and control options. The same can be said for lighting; it must be exterior rated and good in humidity and after that its all about matching it to something that fits in with the rest of the sauna. Once again I run in to a section of blogging that will require its own article and need to cut myself off and get on with the intended subject matter.
In hopes of continued enjoyment your sauna must be maintained. It is worth making a maintenance checklist! Simple care items like cleaning, keeping moisture from sitting too long (airing out) and cleaning glass will go a long way. The bigger items are stove maintenance (replacing and cleaning rocks) and stain/sealer for the exterior wood. Just like a deck these boards will fade and loose color without timely maintenance. General guidelines for staining are every two years and stripping/washing/sanding every 5 years.
Glad you stuck around, next we will try to get back to cladding and heaters and even further down the road we can look in to health benefits of a sauna.