Installing backerboard for shower walls

Here's a few steps for installing backerboard on shower walls. Regular sheet rock won't do for the inside of the shower. Cement board or backer board is perfect for showers, tub surrounds, and other high humidity areas. It requires special masonry screws.

backer board

Cement board is used instead of regular sheetrock in high moisture areas.

It’s kind of heavy and difficult to cut, but it’s very durable. It’s also part of most modern building codes for showers. There is also green board which is easier to work with. Green board can be used in other parts of the bathroom but cement board should be used inside the shower.

cement board blade You can cut cement board with a blade made for cutting cement composite boards. Just put it on your skilsaw and it works really well.

Remember to protect your eyes. Cutting this stuff can be pretty nasty. It will be the worst part of installing backerboard in a bathroom or kitchen.

cutting cement board You’ll need to cut out the shower handle hole, the shower arm hole and the light fixture hole. Fortunately, all these things have cover plates that cover up uneven cuts and holes. You will want to keep the holes fairly small though because some cover plates like the shower arm covers are quite small.


install backerboard

Notice how the cement board is nailed to the wall but it doesn’t rest on the membrane. You’ll want to leave about ¼-inch between the cement board and the membrane.

This prevents possible tears in the membrane from the weight of the cement board. It’s also important to avoid putting screws or nails lower than about 5-inches toward the bottom of the shower pan.

how to build a shower with mortar

The membrane is really tough stuff, but it can still be punctured if you’re not careful. Try not to walk on it while installing the cement board onto the walls.

taping cement board


Once the cement board is in place you will need to tape the joints with special adhesive netting and then put one layer of cement board compound over the tape.This helps make a better moisture seal and sound seal.



Next, applying last mortar layer

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