How to Cut a Window Through a Shower Wall Enclosure

Turn off the water valve to the house. Once the water is off, turn on the water in the shower to allow the water to run out of the showerhead.

Measure over the surface of the shower wall enclosure and mark the location where you want to make the window. Hold a level up to each of the lines to make sure the top and bottom lines sit perfectly horizontal and the side lines sit perfectly vertical. Adjust the lines on the wall as needed.

Cut through the fiberglass or paneled shower wall along the lines that you drew on the wall with a carbide knife. Press just deep enough to get through the shower wall surface, not through the cement board or other waterproof material behind the surface wall. Pull the cut piece of wall covering off the wall.

Find the wall studs in the area of the wall where you cut away the wall surface covering using a stud finder and mark the location of the studs. Hit the wall with a hammer between two of the studs to open a small hole in the wall. With a flashlight, look inside the hole for pipes, and either reroute the pipes to another area of the wall or hire a plumber to do so if you can’t complete this task yourself.

Cut around the inside of the cutout area of the wall with a drywall saw to remove the drywall in the location. Cut the studs from inside the cutout area with a circular saw.

Measure across the opening that you cut out in the wall. Cut two boards to this length. Attach them at the top and bottom of the opening by nailing the boards to the wall studs.

Measure the distance between the board that you placed at the top of the opening and the board at the bottom of the opening. Cut two additional wood boards to this length. Secure them between the ends of the top and bottom boards to create a wood frame around the entire perimeter of the window.

Cut cement boards down to the sizes of the openings around the window frame. Secure the boards to the wood frame with nails. Fill in the spaces around the new cement boards by spreading joint compound along the cracks with a putty knife. Allow the joint compound to dry and cover the drywall with whatever waterproof material covers the rest of the shower.