Installing Fiberglass Showers For A Trouble-Free Shower
Installing fiberglass shower pans is much simpler than building up masonry shower pans.
Fiberglass shower pans can be used at least three ways.
- To replace an existing fiberglass shower pan with fiberglass walls.
- To replace a fiberglass or masonry shower pan where walls are tile.
- In a new built-in installation.
For most replacements of fiberglass showers with fiberglass walls, the entire interior of the shower must come out since the walls overlap the pan lip. Consult your shower pan suppler to make sure this is true.
Installing a fiberglass shower pan to replace an existing pan is described in our article: Fiberglass Shower Pans As Replacements.
For installing a fiberglass shower pan in a new installation, these are the main steps and some of the details. Remember that every manufacturer will have slightly different instructions.
Rough in drain location and design alcove or wall framing dimensions for the type of wall you will install. Will it be matching fiberglass walls for your pan or ceramic tile or some other material? Note that cement board is an excellent backing for either kind of wall.
Prepare the sub-floor. The sub-floor must be a minimum of 3/4 inch construction grade sheathing. Fasten the sheathing to the floor joists with either drywall screws or 8d spiral flooring nails. Make sure creaks and squeaks are eliminated. If you have a concrete slab floor, prepare the surface so it is level.
Provide a hole in the sub-floor to match the shower floor drain. Many of the fiberglass shower pans come with a matching drain which makes installation simpler. Top of the drain pipe usually must be even with the sub-floor or concrete slab.
If possible install the shower floor on a bed of 30 lb. roofing felt to compensate for any irregularity in the sub-floor or slab. You could also use an appropriate adhesive for the same purpose. Depending on the manufacturer, the pan may need support underneath. The recommended support is often foam.
Now set the fiberglass shower floor in place. Especially if you have a ceramic wall or another type of solid wall, you may want framing under the flange of the pan for support. Caulk between the pan and the support pieces. Make sure the pan is level.
Install the drain using the correct procedures. Usually the drain is attached to the waste pipe with a rubber washer first, then a fiber washer, then finally with a nut. The nut is usually tightened hand tight then 3/4 of a turn. But you will get instructions on tightening with the drain.
Screw the edges of the pan to stud walls. Then you are ready for installation of walls.
If you think you might like to go back with a ceramic tile shower floor, check out our ceramic tile installation article. See that article at this link...