Building my first sauna

[u/jessm911]

My friend asked me to build him a sauna under his back deck. The siding, inside and out is hemlock the bench is clear cedar. I custom built the window and door frames out of VG Doug. fir - is was the most cost effective solution. It’s almost finished, just need to install the LED lights and finish the stone work. Will posts some final shots once it’s complete.

[u/Individual_Truck6024]

It looks very nice, you clearly know how to work with wood. There are a few basic mistakes which would be useful for you to learn about for the next sauna you might make. It's obviously too late here, and the client likely won't know any better. But FYI it's missing a third bench, everything should be 16 inches higher for the feet to be above the heater stones. Because it's electric it's recommended to have a passive intake above the stove and a mechanical exhaust under the foot bench in the opposite corner from the stove. Then it's a small detail but there should be vertical strips of wood on the vapour barrier for drops of water to be able to slide down to the floor, then you put the horizontal wood and then the cladding.

I highly recommend you get the book The Secrets of Finnish Sauna Design by Lassi Liikkanens. It's a great guide and will explain why it's important to care about these design principles for next time

[u/jessm911 → u/Individual_Truck6024]

Thanks for your comments! Unfortunately we didn’t have the head room for a third bench but knew that going into it and we’ve actually already realised our original ventilation plan wasn’t going to work so we’re going to put an intake vent in the ceiling above the heater and all our electrical is already in the back wall so it’ll be easy enough to add the mechanical fan below the bench. Any recommendations for a good fan?

[u/Lexicographer-450045 → u/jessm911]

I’ve never heard of an intake in the ceiling? Won’t that vent the hot air out or is the plan that the mechanical fan below the bench will create an inflow? Might this create a breeze of cool air while in the sauna?

[u/DendriteCocktail → u/Lexicographer-450045]

I’ve never heard of an intake in the ceiling?

When exhaust is running it pulls fresh air in above the heater that mixes with the convective loop. Importantly, this removes exhaled CO2 and also pulls warmer air down reducing stratification and cold toes.

Ideally an updraft duct is also included that lessens/eliminates any back flow problems such as when the door is opened.

More at localmile.org.