Lessons Learned

These are the things I discovered the hard way. None of them are obscure — they're well-known to experienced sauna builders — but they're not the things sellers tend to mention at the point of sale. Consider this the briefing I wish I'd had before I started.

Planning and purchasing

• Get multiple electrical quotes. The electrician referred to me by my sauna supplier quoted 50% above market rate. A referral is a starting point, not the only option. Always get at least one independent quote.
• Ask about control unit specialists before you buy. Some control units require electricians with specific prior experience installing that unit. This is a real constraint that narrows your contractor options significantly. Ask before you commit.
• Confirm the wire configuration in writing. My 240V circuit needed a neutral wire — a detail that affects which cable you run and potentially your panel. Get this from the manufacturer before your electrician does the rough-in.
• A sauna kit is not a complete sauna solution. Whether you buy a kit or build from scratch, framing, insulation, vapor barrier, flooring, drainage, ventilation, and electrical are all still your problem. The kit gives you the cedar. Budget for everything else separately.

Construction

• Vapor barrier goes on the warm side. Between the insulation and the cedar cladding — not behind the insulation. If your contractor puts it on the wrong side, moisture accumulates in the wall cavity. Check before the cladding goes up.
• Clear grade means no knots. Knots concentrate heat and can become burn hazards on bench slats and wall cladding. Don't accept substitutes, even small ones.
• Mineral wool only — not fiberglass. Fiberglass loses its R-value in humidity. Inside a sauna, this matters.
• No finish on cedar — none at all. No stain, sealant, oil, or paint anywhere inside the sauna. It traps heat, off-gasses, and goes tacky at temperature.

Bench design

• A 20″ bench will not accommodate lying down. You need at least 24″. Confirm your intended use before fixing the depth — it's hard to change later.
• Install beams on edge, not flat. A 2×6 installed with the 5½″ face vertical is approximately 13× stiffer in bending than the same beam laid flat. Always install on edge, and make sure your contractor understands why.
• 36″ upper bench is on the taller end. At a vaulted ceiling averaging 78″, this leaves 42″ of headroom above the seat — workable but worth confirming at your specific ceiling geometry before building.
• Heater clearance at the bench is a hard constraint. Know the minimum clearance before you lay out the bench. In my build, the cross supports stop 65″ from the non-heater wall, leaving 27″ clear near the heater.

If you want to talk through your build

I went through this process the hard way and I'm happy to save you some of the same trouble. If you're planning a sauna and want to talk to someone who's been through it — the real costs, the decisions, the things to watch out for — feel free to reach out.