A leaking shower pan is the result of some crack or tear in the membrane. If you discover that the shower pan is leaking, the only repair option is to replace the shower pan. A cracked or damaged water pan that leaks will continue to leak, regardless of any efforts you to put in to seal the crack or damage. The integrity of the shower is now in question, and that is why this article is discussing the replacement of the damaged shower pan as opposed to repairing it.
Step 1 - Purchase Materials
The first step in a project such as this is to go to a home improvement center or a kitchen and bath store to purchase the materials necessary to replace the leaking shower pan. Try not to purchase any stop leak product or any similar type of offering. Such a product will not work on the leaking shower pan and will only delay the inevitable task of replacing it. You will need grout and a replacement shower pan with liner, as well as any tiles necessary to reset the floor.
Step 2 - Take Up the Old Flooring
Using a chisel and a hammer, take up the floor tiles in the existing shower. The tiles need to be removed in order to gain access to the shower pan underneath. You will be able to replace the flooring with new tiles once you remove the leaking shower pan.
Step 3 - Pull Up the Membrane and Shower Pan
Locate the protective membrane and shower pan that is underneath. Pull the membrane away and shower pan away. Pull up the old sub flooring and set a couple of large floor fans near the shower to dry the flooring. It may take a few hours or can be left on overnight to completely dry the floor. Once the flooring is dry, place new sub flooring down using the plywood that you purchased from the home improvement center.
Step 4 - Replace the Membrane and Shower Pan
With the new sub flooring set in place, you can place a new shower membrane and tub. Make sure that the membrane completely covers the sub flooring to provide protection against any future leaking. Set the shower pan and new tile floor in place using the grout and rubber float to grout the tiles. Allow the tiles a day to set up before completing this task. Test the water to make sure that the leaks have been dealt with properly.