The Benches
Bench design is where the sauna becomes yours — and where some of the most consequential functional decisions are made. Heights, depths, and structure all interact, and changing one affects the others.
Heights
| Tier | Height AFF | Character |
|---|---|---|
| Upper bench | 36–40″ | Hotter, closer to ceiling. My choice: 36″ |
| Lower bench / step | 18–20″ | Cooler zone, serves as step-up. My choice: 18″ |
The step between tiers should be 18–20″ — comfortable to climb in a hot, humid environment. Always verify headroom at the upper bench position against your specific ceiling before fixing the height.
Depths
| Intended use | Minimum depth | Recommended |
|---|---|---|
| Sitting only | 16″ | 20″ |
| Sitting + step-up | 18″ | 20″ |
| Sitting + lying down | 24″ | 26–28″ |
I went through several depth iterations before landing on 24″ for the main bench — wide enough for lying down, deep enough for real structural support from the beam-and-ledger system. Confirm your intended use before fixing the depth.
Structure — wall-to-wall beams on ledgers
After exploring legs, knee braces, and diagonal supports, I landed on wall-to-wall beams on ledgers. This is what I'd recommend to anyone building a custom bench:
2×6cedar beams spanning the full room width, resting on ledger boards lag-bolted to the side walls- Beams installed on edge — the 5½″ dimension vertical, not horizontal. This makes them approximately 13× stiffer in bending than the same beam laid flat.
- Back edge supported by a ledger on the back wall — three support lines total
2×4cross supports, 24″ long, evenly spaced along the bench length- Zero legs — the floor under the bench is completely open for cleaning
Cross supports must stop before the heater zone. In my build, the last cross support's outer edge sits exactly 65″ from the non-heater wall, leaving 27″ clear near the heater. Always follow your specific heater manufacturer's minimum bench clearance — typically 18–24″.
Seat slats
Clear cedar 1″ × 3½″ slats, running perpendicular to the beams. Leave small gaps between slats (approximately ¼″) for drainage and air circulation. No finish of any kind — bare cedar only. Blind-nail with stainless steel fasteners.
Based on one 2×6 beam and four 2×4 cross supports per bench. Adjust slat count to match your layout.