How to Install Membrane Waterproofing to a Shower

waterproof membrane under showering water
  • 4-8 hours
  • Intermediate
  • 100-500
What You'll Need
Tape measure
Cement board
Rubber cement
Waterproof tape
Shower membrane

Membrane waterproofing is a very important part of your shower area because it helps prevent splashes and leaks. Apart from this, the membrane on the shower floor will help direct the water flow down to the drain. The waterproofing must be installed correctly to avoid fungi in your shower area. A loosely-installed waterproof membrane can also cause water to seep down to the subfloor, creating damage there.

Step 1 - Checking the Subfloor

Check the subfloor thoroughly before you start installing the membrane. Make sure that the joists of the floor and the sheathing of the subfloor are in a good condition. However, if you notice some kind of damage in the flooring, repair it as soon as possible and do not resume the installation until you finish the repairs.

Step 2 - Taking the Measurements

Use a tape measure to measure nine inches up the shower walls from the drain. Make a lap in the membrane waterproofing which measure between nine and 12 inches. Remember that the length of the lap depends on the type of waterproofing you are installing. If there are some nails on the floor, pound them down to prevent future punctures in the membrane waterproofing. Don't wear shoes when installing the membrane to avoid damaging it.

Step 3 - Mixing the Cement Mud

Create a channel down the subfloor in such a way that the drain is flush with the structure of the subfloor so the membrane waterproofing will direct the water toward the drain. Make a mixture of cement mud and carefully read the instructions on the pack for excellent results. Remember to keep the mixture a bit thick so that it will not run as you apply it.

Step 4 - Laying the Membrane

Lay the membrane waterproofing in the shower and adjust it carefully until it fits exactly in the space. Put the shower membrane into a corner to avoid wrinkles. Cover the liner around the shower drain with rubber cement. Apply half an inch of cement to every inch of waterproofing material.

Fasten the membrane waterproofing in place by placing some pieces of waterproof tape in the corners. When you lay the waterproofing material on the shower floor, make sure that you cut a hole that fits the opening of the drain. Be careful not to cut a hole which is too large. Put the cover of the drain back into place after you finish. You should test the waterproofing for leaks after installing it. Confirm that the membrane is resistant to leaks, and then you're ready to install concrete or tiles on the walls of your shower.

Step 5 - Installing the Concrete

Keep the boards of concrete at a distance of approximately one inch from the lower edge of the membrane waterproofing. Use a pencil to trace the edges of the concrete boards and cover the membrane with cement. Place the concrete over the cement and let it dry thoroughly.