Build A Moisture-Proof Steam Room

To protect your walls and flooring from water damage, it is best to moisture-proof your steam room. It is impossible to moisture-proof a room 100 percent, but if you follow these tips, you can minimize the damage that moisture can wreak on your structure.

Installing the Shower Pan

Install the shower pan before finishing the walls to your steam room. If you do not have experience working with tar, you should hire a professional to hot mop the pan.

You can use a pre-built fiberglass shower pan, but make sure that it is the correct size—they generally aren't made custom.

Maximizing Drainage

Drainage is one of the most important aspects in constructing a moisture-proof steam room. You should have your shower pan graded to drain in the center. It also helps to keep out moisture if you slightly pitch the bench and threshold.

If your steam room has a window, you should pitch the ledge as well. Such gradations help to drain out the water faster instead of letting it pool to cause damage.

Wall Construction

If you are finishing your walls with stone or tile, you need to use concrete wall board or a similar waterproof backing. If the interior walls are fiberglass, you only need to seal the seams with silicone.

You can also use glass walls, which do not allow moisture through. Glass walls still require waterproof backing, but you only need seal the seams. Glass walls are also very appealing to the eye and create a beautiful appearance.

Steam Room Doors

If you have a standard sized doorway, you can install a pre-fabricated door. Otherwise, you should order a custom door and install it. Either way, you must seal the seams where the door meets the panels.

Installing Fixtures

If your steam generator is located outside the steam room, you must seal the area where the steam nozzle enters into the wall. You also need to seal around any control units that are installed.

Purchase and install a light cover that is designed for wet environments. The light cover should come equipped with a gasket to keep out moisture.


When applying sealant, err on the side of caution! Be generous in your application. Water and moisture can seep through cracks of any size.