Getting your sauna foil vapour barrier right

If you're building a DIY sauna, choosing the right sauna foil vapour barrier is probably one of the most critical steps in the whole process. It's one of those "invisible" components that you'll never see once the cedar boards are up, but you will definitely notice if it's missing or installed poorly. I've seen people try to cut corners here, thinking a standard plastic poly wrap will do the trick, but a sauna is a completely different beast compared to a standard bedroom wall. You're dealing with extreme temperature swings and a massive amount of humidity, and that combination can wreak havoc on your home's structure if you don't manage it properly. ...

May 2, 2026 · 6 min · Mitali Melchor