knowledge-kitchen / domestic-construction

Russian Banya / Finnish Sauna

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Research into the construction of a Russian banya (or Finnish sauna) - a necessity for any home. Construction began 2 December 2024 and was completed about 2 months later.

Model

Banya/sauna plans. top front side

Foundation

There are two basic types of above-ground structural foundations:

I ended up using a pier foundation, with treated 4x4 posts inserted into Camo deck blocks, with each block sitting on a 4” hole filled with gravel.

Dimensions

Most American sources advise to build a sauna/banya no taller than 7’, otherwise, they say, lower areas will not retain heat as it rises. Apparently, this is utterly wrong. Finns and other sauna enthusaists say to build no less than 8 1/2’ tall for proper hot air circulation and comfort when raising arms.

My sauna/banya’s hot room dimensions are approximately 8 1/2’ tall with 5 1/2’ x 7 1/2’ floor space. The changing room (or predbannik) floor space is 3 1/2’ x 7 1/2’.

Occupancy

Some recommendations I’ve found for occupancy, which seem correct to me:

Floor

2x6 treated lumber for floor joists. I used 3/4’ oriented strand board (OSB) for subfloor, although plywood would generally be recommended for more moister resistance. On top of the OSB, I’ve added a layer of tar paper. On top of the tar paper, I sloped the floor towards a central drain cutout using the Ben square method. Above the sloped strips is cement board, with large slate tiles on top.

There are various views on whether floor insulation is necessary. I did not use any in order not to make it any easier for opportunistic mice to find a cozy home. I have not noticed any problems with heating the room, although the floor is certainly cold to start.

While I have not done so, some banya/sauna builders place “duckboard” panels on the floor for added comfort. These are removable sections of 1”x3” or 1”x4” wooden slats with 1/2” spacing between the slats. Water drains between the gaps and does not pool up on the boards.

Framing

Wall framing

Roof framing

Windows

Insulated tempered glass is preferable, although many use whatever regular glass is available. Any window will reduce the heat retention. As long as the stove is strong enough, this is not a problem.

I have a fixed insulated tempered window in the hot room, a small regular piece of glass removed from an old door used as a window separating the hot room from the predbannik, and a cheap vinyl big box store tilting basement window with a bug screen high up in the predbannik wall to the outside.

Door

Vents

Insulation

Interior

Wood and nails

Heater

Benches

Lighting

Most pundits agree that lighting should be discrete and dim.

In the predbannik, I retrofitted a Danish-style PH5 lamp with a solar-powered LED bulb. In the hot room, I placed the solar-powered LED bulb hanging under the bottom bench for ambient light.

References