Shower pans get old and may even crack and leak water into the subfloor. The solution in this case is to replace them. Given that you cannot remove a shower pan without damage to the surrounding wall tiles, you should focus on doing as little damage to the wall as possible. That entails only removing the row of tiles adjacent to the shower panel.
Open up the lower layers of the shower wall, loosen up the shower pan then disconnect the shower drain before removing the shower pan. Replace the shower pan by positioning it on the shower floor, connecting the shower drain then placing it on the shower floor before covering up the wall around it.
If you don’t have experience with shower pans, mixing mortar for shower pans or other DIY skills, you better not attempt this project since you might have leaks and breakages in the future. Call for a plumber instead.
How to replace a shower pan without removing the tiles
For this procedure, you need a reciprocating saw, hammer, utility knife, drill (optional), pry bar, screwdriver, and pliers. Replace the shower pan by following these steps:
1. Open up the lower layers of the shower wall
Open up the lower layers of the shower wall by removing the baseboard, drywall and ceramic tiles. The lower parts of the wall will be made up by wainscoting, center support beams (for framed showers) and studs. Open these three layers with your reciprocating saw to expose the shower pan. Be careful not to cut any wires or pipes in the wall while doing this.
2. Remove the drywall
Pry the drywall away from the tub using a pry bar. There will be studs on top of the tub that you can use to pull up the drywall. Remove all of the screws in the face of the drywall that are holding it onto the studs. Then remove all layers of drywall.
Sometimes there is an extra layer of sheetrock (thickness) at this point between tiles which keeps your shower wall flat and waterproof. Remove all surface paper from this extra thick sheetrock with a sander. This helps it soak up water properly after you pour in concrete into your shower pan later.
3. Remove tiles next to the shower pan
With a pry bar, remove the corner tile next to the shower pan. Remove any adhesive remnants under it using a scraper or putty knife, and clean it with a solution of water and TSP (trisodium phosphate).
The best way to avoid removing more tiles than necessary is to look at how far up the wall can be worked on so that the shower pan is freed. If the pan can come free with only one layer of tiles removed, don’t remove other wall tiles.
4. Clean up the debris
To avoid the mess and inconvenience later, clean up the debris from all around the shower. Remove all of it to a designated area for dumping in order not to get any of it into your new work area and dirty up what you have cleaned already. This also helps avoid accidents such as tripping in the next steps.
5. Loosen up the shower pan
After cleaning, the first step is to loosen up the existing shower pan. Loosen it by tapping around the perimeter with a hammer and chisel. Loosening the cement and caulk helps you remove the old pan.
Next, unscrew all of the screws that hold down the damaged or rusty shower base then pry out any nails from underneath if there are any. After this, you will be able to remove your existing pan without too much trouble.
For pans that have been sealed in place with silicone caulk, use a heat gun or hairdryer to soften up this sealant so it can be scraped away easily and separated from metal surfaces underneath it.
6. Disconnect the shower drain
Disconnect the shower drain from the shower pan to avoid damage to the drain and other parts in the floor. Disconnections vary by model but it usually involves removing a little round cover on the top of the drain, or unscrewing a clamp at the bottom of the drain that fits around the shower drain pipes preventing water from draining into your floor.
Use a flat head screwdriver to remove both clamps and set them aside so you still have access to unscrew this part back if needed later.
7. Remove Drain Cover and Grommet
Next, remove any screws holding down the gasket in place (if there are any), then use a utility knife to cut through the sealing material around it being careful not slice up your finger. Some gaskets can be quite stiff and need prying up the edge with a flat head screwdriver or other thin tool like a putty knife.
With a little force, you should be able to remove all of the gasket sealant from around the drain hole.
8. Remove the shower pan
Remove the tile caulk from around the shower pan and then place a pry bar under it to lift it out of position. Use caution as some are still stuck in place even after all that effort.
If you had to dismantle any plumbing fixtures such as faucets or handles at this point it’s a good time to replace or repair them.
9. Replace the shower base
Next, replace the shower base. Remove a section of tile from around the drain and replace it with a new pan liner. Follow manufacturer’s instructions for cutting out the pieces that need to be replaced, such as damaged grout or sealant.
Make sure you have properly positioned the shower drain so that it aligns with the cutout on the shower pan. Once the shower pan is in place, connect it with the pop-up drain assembly you took off earlier.
10. Cover the walls
Flip the walls back over so you can reinstall them in the existing holes. If the walls are damaged, replace them with new ones from your local home improvement or hardware store. Notch out around pipes and replace any broken wall tiles. If you didn’t find the ones matching the rest of the wall, consider painting the tiles.
Apply silicon caulking all around where it meets the floor, including along several inches of each side that won’t be coming in contact with anything else, and replace the tile section you removed to access the shower pan. As long as you used silicon sealant when replacing your tiles, moisture will never leak into your house from inside these joints.
Differences in removing fiberglass and tiled shower walls
When removing a shower pan from the shower floor, the type of shower wall determines the method used as follows:
Tiled shower walls
Tiled shower walls use caulk between the wall tiles and the shower pan. The caulk can be easily removed with a knife. The drain is then disconnected from the shower pan which is then pried out of the shower floor.
Tiled shower walls have an additional layer of waterproofing membrane between the tiling and the shower pan. These shower walls are most often found in commercial installations. Tiling is tedious, labor-intensive work but it does look nice when done properly.
Fiberglass shower walls
Fiberglass material is poured into a mold to create a shower pan liner that fits over the top of the subfloor. This material cannot be pried out as easily as tile caulk can be removed but there are ways for this to happen without removing any of your tile surrounding your fiberglass wall panels. Fiberglass panels require a slightly different method of removal.
A saw is necessary for cutting a fiberglass shower wall pan from the floor. If cutting your own hole in a fiberglass wall, take care that you cut close to the perimeter of the drain which remains after removal of the shower pan [there should be a copper pipe protruding].
The holes are then cut in each edge where angle cuts meet and the bottom of the new tub will sit on top. A reciprocating saw with metal blades works well for this purpose although multiple bathroom remodels have proven that most do-it-yourselfers don’t have one at home.
With this knowledge, you should replace your shower pan without removing too many tiles from the wall. However, you still need to have some plumbing skills to avoid making a mess of the shower floor which can lead to a leaking shower pan and a lot of repair costs later on.