This Cement Backerboard Tile Underlayment Is Perfect For Laying Your Shower Tile Or Bathroom Wall Tile For A Tub Surround.


Before you install your shower tile or bathroom wall tile to your tub surround, you'll need to waterproof the walls and the framing underneath.

These are both wet areas of the bathroom, So you'll need to use Cement Backerboard, and Roofing tar paper to create a waterproof tile underlayment for your Shower Tile and bathroom wall tiles for your tub surround.

To install the backerboard, you must have a vapor barrier between it and the wooden wall studs.

The trick is to install Tar paper, so it overlaps correctly. You'll want each piece of tar paper to overlap the piece below it.

Cement Backerboard comes in 3 X 5-foot backerboard sheets. They can go up vertically or horizontally. Cement Backerboard makes for the perfect wall substrate for the wet areas of a shower or tub surround.

It's also the perfect Tile underlayment for your shower tile.
And when installed correctly will give you many years of protecting your shower construction.

Cement Backerboard is not waterproof, but it is dementionally stable, even when wet. In other words, when they get wet they won't swell. But those wood studs you're protecting will. So you must create a good watertight barrier between your studs and moisture.

Not only that but any swelling behind your Tile Underlayment will cause not only the grout but also your beautiful new shower tiles to crack.

What You Need To Know Before Installing Your Shower Tile Or Tub Surround Tile Underlayment

* Since you're already stripping your shower down to the studs, Why not install a shower niche?

* When tiling a tub surround, the bathtub can introduce additional problems. If your tub is level, you can plan on laying a row of full shower tiles at the tubs top edge. But if your tubs not level you'll need to lay a row of tiles that are at least three-fourths of a tile high to hide the un-level appearance.

* If you are installing bathroom wall tile to a tub surround, You need to only install the Cement Backerboard 12 inches above the tub. For a shower enclosure extend the Cement Backerboard, at least, six inches above the showerhead.

* Before you can install your new Cement Backerboard,  you'll need to Remove the old tile underlayment down  to the studs
Once you've done this, be sure to remove all the nails from the studs.

* Measure to see how thick the Cement Backerboard must be in order to match the surrounding drywall surface.

Step 1-Install Staple Roofing Tar Paper To The Studs

To install your Tar Paper staple it to the wall studs completely covering the entire surface which will be inside your shower or tub surround.
A two-inch overlap is plenty for a horizontal seam but walls are vertical, so you'll need to make your overlapping six inches, And at the bottom of the barrier, you will want it to overlap on the shower side of the tub or shower base.

Step 2-Cutting Your Backerboard Sheets

Start at the back wall of the tub or shower and cut your backerboard to fit this wall. All backerboards are cut by scoring and snapping. So you won't need a saw. All you'll need is a regular utility knife.


 Make your marks for cuts.  Then lay Your Backerboard across a 2x4. Align a straightedge against your mark and use a sharp utility knife to score the front of the board

Snap, your board along the score line. To do this, you will need to bend it away from the cut side, and to complete the cut slice the paper backing on the opposite side of the board.

Step 3 Installing Your Backerboard Sheets

While installing your Backerboard sheets, You do not want to butt them up against one another. You need to leave a small 1/8 inch gap between each board.  Including any corners, walls to ceilings, and walls to tubs or walls to floors. There needs to be room for expansion and contraction.

Wood is always expanding and contracting , and you don't want this movement to interfere with your bathroom wall tile.  So by leaving the small gaps between your Cement Backerboard sheets, this will allow for for just the right room for movement. Backerboard itself is very stable, but the wood studs you're attaching it to are not.

You will also want to end your backerboard sheets at about 1/8 inch above the top of your shower pan or the surface of your tub. You do not want to run the board over the edge because it will cause the backerboard to bow out making for an un-flat wall.

You also need to allow the tub or shower base to move a bit because tubs move when they have so much water. And guess what, it’s also attached to studs. So once again you'll have to allow for that movement.

Drive backerboard screws into the backerboard sheets and through the studs every six inches. And be sure to sink the heads of the screws just below the surface of the backerboard.

For additional protection, you can apply Asphalt roofing cement to the flange of the tub. For a shower, this would be the vinyl shower pan.

What If You Don't Have Enough Studs To Attach All Your Backerboards?

If you don't have enough studs to attach each edge of all the backerboards. You'll need to add more studs.

Simply screw the additional  2 X 4’s to your present framing. It doesn't matter if you install them vertically or horizontally. Your goal is to make sure that every edge of the backerboard is screwed directly to a stud, so you wind up with a solid wall. And the flatter your backerboards, the easier your  shower tile installation will be.

Step 4-Make Your Pipe Cutouts

When you're done with the back wall, move to the wall with the pipes.

Measure and mark your cement backerboard for the center of the each pipe penetration you'll need, and then drill each hole using a carbide tipped hole saw about 1/4 inch wider than the pipe. Install the backer board sheets for this or any other wall you're installing them to, in the same manner as you did for the back wall.

Another way to make your pipe holes is by using a masonry bit. Drill a small hole in the center of your mark, then use your backerboard knife to score the outline of the hole. Repeat this on the other side of this cement backerboard and then punch the holes out with a hammer.

Step 5-Tape the joints

Press fiberglass mesh tape along each joint of the Cement backerboard.

Mix up a small batch of Thinset Mortar and use your trowel to lay a thin coat of it over the mesh tape. Feather the edges and scrape away any high spots.

Use a silicone caulk to seal the spaces between the tub or shower pan and the backerboard. Don't concern yourself with smoothing the caulk as it will soon be covered with your shower tile or your bathroom wall tile for your tub surround.

First you'll need to plan your Stone or Ceramic Tile Layout, Then you'll move on to

 installing  your shower tile or bathroom wall tile to your tub surround.

Leaving Tub Surround< > Go To Ceramic Tile Shower