These pans are replaced due to a leaking condition, as in the case below, or the pan has become unsightly. Nevertheless the procedure is the same. In the first photo, we see the intended project. This pan had ed and was leaking through the sub-floor into the ceiling on the lower floor. The construction dates back to approximately 1990 and the tile was installed over water resistant gypsum board above the fiberglass pan.
You can see from these photos that there was water damage visible to the surrounding wall areas.
The glass and aluminum shower enclosure was removed and the removal of the shower pan commenced. A 3 ½" dry cut off saw was used to cut through the tile-work and substrate in a grout joint 12" above the shower pan. The grout joint was chosen so that a new substrate and tile could be installed in the old tiles place.
Note the use of a shop-vac and window fan to keep the dust and debris to a minimum.
Next, a pry-bar and hammer were used to loosen the tile and substrate (drywall) away from the wall studs.
During the demolition, I noted that the method used was correct for that time. The water resistant drywall had the taped edge ¼" above the pan flange, there was no membrane behind the drywall, a skim coat of adhesive had been applied to the drywall before the bond-coat, and the drywall had been nailed properly. However, the enclosure was a wet area and the installation had failed due to moisture.
Once the tile-work and substrate had been removed, the rubber drain compression flange is drilled out to free the pan from the drainpipe. This can vary with installation and can sometimes be made of lead. Nevertheless, once the flange is adequately drilled out, the pan can be lifted out.
Note the large in the pan, which accounted for the leak into the sub-floor.
Next the area is cleaned and vacuumed then inspected to determine whether the sub-floor or wall studs need to be replaced.
Once the necessary changes have been made, the new shower pan is properly installed and water tested.
In these series of photos, note how the new pan is protected with duct tape and asphalt impregnated building paper. It is important to protect these easily scratched surfaces from damage and will result in a better-finished project. The next step is the installation of the 15-pound roofing felt membrane or its equivalent. Remember to overlap any seams and corners the required 4". Note how the wall studs are marked with blue tape for the fasteners in the next step.
Also note, in the above photo, where some additional drywall was removed for a mortar bed on the left side of the pan. The drywall was unstable and had to be removed due to water damage. A flashing should be installed over the new membrane that extends under the old tile work and substrate as indicated in the illustration below. This will allow any moisture trapped behind the tile-work to flow down the new membrane.
The reinforcing wire, minimum 2.5 pound, is then installed with the required 2" overlap at all seams and is fastened with the required fasteners. The reinforcing wire is cut at both 90° corners. A layer of duct tape secures the membrane that must overlap the pan flange to the protective paper making the installation of the mortar bed simpler. A wood template is constructed that will be used to cut off the new mortar bed to an "on-plane" thickness using the existing tile-work as a guide. The cutting edge of the template will cut the mortar bed ¼" deeper that the existing mortar bed. This will allow the installation of the new tile and bond coat later.
Tile Doctor Tip: By constructing the template now, the template can be used to ensure that the following "scratch coat" is not too thick to interrupt the application of the "brown coat."
"Wall mortar" is then forced into the reinforcing wire to fully imbed the wire to form the "scratch coat." The scratch coat is necessary in the area where no solid backing is present. This photo show the tool used to form the "scratch coat". Note in this photo that a "one coat" mortar bed was installed. This was possible as the area was fully backed by a series of existing wall studs and was therefore solidly backed. Next the "brown coat" is applied and consists of "wall mortar" forced or "keyed in" to the "scratch coat" using a finish trowel. The excess mortar is cut off using the template constructed earlier.
Tile Doctor's tip: Be careful to run the template against the existing joint of the old tile-work and new mortar bed as well as the point where the new mortar bed meets the new shower pan. Also, be sure to cut off the excess mortar at the corner joints. This will make the application of the new bond coat and tile easier.
At this point, clean the existing tile-work and allow the finished mortar bed to cure. Next some of the protective paper is removed exposing the upper part of the pan where the new tile and pan will meet. Portland cement thin set mortar is mixed per the Manufacturers instructions and is applied to the cured mortar bed. The thin set is first "keyed in" to the mortar bed using the flat side of the trowel then is combed out to a uniform thickness using the ¼" X ¼" notched side.
Be sure to remove excess thin set from the upper and lower perimeter joints making the installation of the tile and cleanup easier. The tile chosen for this replacement comes from the Manufacturer in 12" X 12" sheets. The tiles are held together by polymer based "dots." The sheets were pre-cut for the opening size. The pre-cut sheets were placed in the freshly combed thin set mortar, were beat in, and were aligned and held steady with spacers and or wedges. Remember to remove the thin set from the joints at the new and old tile as well as the lower tile and pan joint.
In this case the new tile forms a perimeter around the old tile-work. This tile was installed with thin set after the wall areas were thoroughly sanded to ensure an adequate bond between tile and existing drywall.
Finally, the tile-work is thoroughly cleaned and any excess thin set in the joints is removed in preparation for the grouting process. After the thin set has cured, the grouting process begins with mixing the "sanded" grout per the Manufacturers instructions. The area to be grouted is moistened with a damp sponge. The grout is troweled into the joints firmly areas small enough to be finished before the grout sets and becomes unworkable. The trowel is held at a 45° angle to the tile.
The excess grout is then cut off the face of the tile and the excess is returned to the grout bucket. The grout is then tooled with the grout sponge. Any pinholes, voids, or low spots are filled to a smooth and uniform color. A final wipe with the sponge, held at a 45° angle finishes the joints. Be sure to cut the excess grout out of the joint between the old and new tile-work and the joints at the 90° corners, as well as the pan and tile interface. These joints will be filled later with a sealant instead of hard grout.
After the grout has initially cured, install the sealant at the required locations. Use a damp grout sponge to tool the sealant joints in a way similar to the grout joints. Use a sealant that is color matched to the grout.
Here is the finished project ready for the installation of the new shower door enclosure.