Building a sauna door

This is how I build a sauna door. I start with the rough opening measurements and work my way in. Here is the door frame (left) and the frame of the door itself. I built the one on the left, and then like a nesting doll, built the other one inside. I left enough gap on the sides so the door can swing out of the frame with some hand planing. Be careful to not add fasteners where you’ll be planing the non-hinge side of the door.

Then, I built the interior of the door (below, right). Instead of measuring with a tape, I cut 2x4 boards a little long, set them above their position and marked the cuts with a utility knife. It’s important to be accurate with doors. I ripped my vertical 2x4 boards to reduce weight and square boards up.

I did the diagonal corner-to-corner square-check on the cedar door frame, then stamped the corners of the 2x4s with mending plates. Content that it wouldn’t move, I took it out of the door-frame and added a horizontal and diagonal brace using the same utility-knife measuring method. You’ll want to make sure your diagonal braces start low on the hinge side and rise up to the other side of the door for best mechanical effect.

I trace and cut 1.5” rigid foam. Make it tight to help keep the door from sagging.

I don’t yet attach the frame around the door in case something needs to be adjusted. I attach tongue & groove (t&g) cedar siding on both sides. My door frame material l is wide enough to cover the ends of the cedar siding. Cedar siding is not 3/4” thick! I planed the rough face off on the interior and left the siding rough on the exterior.

Because I didn’t have enough space to evenly the bottom of door with 5” reveals, I split the difference and ripped a “half” board for the bottom and top of the series.

The frame around the window was tough. I chiseled the spot where it meets the verticals contact the horizontal siding below so that their joint is sloped to the exterior.

I put high-quality clear silicone on all exterior joints before nailing things down with 2.5” 16-gauge stainless steel nails. My air nailer died before I started, so I went quickly and bought the second cheapest one I could find ($44).

Traced the hinge cut-outs with the utility knife. Then used my plunge router to clean it out. Using a knife first ensures that the wood doesn’t splinter past the hinge location.

I replaced one of the screws in the top and middle hinges with a long stainless screw to add strength. All done and installed tonight.

This door cost about $400 for supplies. The acrylic window was about $50. Each hinge was $5.50! Cedar is not cheap! (If you need a custom sauna door, let me know.)