You are standing in a framed room with a roll of foil and a staple gun, and the part nobody warns you about is the seams. The foil itself is the easy bit. Every overlap, every staple hole and every cut you make for the heater feed, the light wiring and the vents is a place where hot, wet air can get behind the barrier and into your framing. That is the failure you do not see for a few years, and then you see it all at once.
This tape closes those gaps. It is aluminum foil tape built to sit at sauna temperatures, 2 in wide and 164 ft on the roll, and it is the tape we would use on our own build over any general-purpose duct tape. Adhesive that is fine behind a laundry-room wall is not fine at 190°F.
The one thing worth knowing
Overlap your foil sheets a few inches, then tape the seam, rather than butting two sheets together and taping over the joint. The overlap is what actually sheds moisture; the tape is what holds the overlap shut. Wipe the foil clean and dry first, lay the tape centered on the seam, and press along its whole length with your hand or a plastic squeegee. Pressure is what sets the adhesive, so a tape that is laid on rather than pressed down will let go later. Do the wall-to-ceiling corners too, and patch tears and staple holes as you go. All of this is far easier before the paneling goes up than after.
How much to order
Add up the length of every seam in the room, plus the perimeter of each opening you have to cut around, and leave yourself margin for corners and patches. If you would rather not guess, tell us the room size and what you are lining and we will work it out with you. Send over your dimensions or call the Bens at (844) 565-1113 and we will tell you how many rolls of foil and tape the room actually takes.
Prebuilt
Sauna Brushes
Vents