Taping Backer Board Joints Floor Dry Before Tiling

In order to properly seal the joints a mortar is spread over the seams between the boards and a fiberglass tape affixed to the mortar.

Taping backer board joints floor dry before tiling. You shouldn t add any backer board over the top of it. But these problems can be avoided by this one simple step. Screw the drywall to the studs. Then a coat of thinset gets flat troweled over the seam.

Alkali resistant mesh tape. Secondly once the self leveler is dry you can adhere tile directly to it. If there are cracks larger than 1 8 inch in your concrete subfloor those should be patched and filled with a cement patching compound. Doing them improperly can lead to big problems down the road.

You could however install backer board first and then self level on top of that. It should go directly over the thinset and on to the backer board on the edges. If you plan on installing the backer board and tile on stud framed walls you have to seal the joints of the backer board before moving on to install the tile. Once you put the tape down on the joint cover it with more thinset.

Run the drywall knife over the mortar to create a smooth finish and remove any excess material. If you ve made any adjustments to your floor you must allow them to completely dry before installing the new floor. Push the mortar through the mesh tape and into the 1 8 inch space between the backer board and the drywall. Do a dry run and lay the backerboard down to fully cover the area you plan to tile.

Once you have filled the gap with thinset apply fiberglass tape. Mix thin set mortar according to the manufacturer s instructions and apply a thin coat over the fiberglass tape with a drywall knife. For tile backer boards such as durock wonderboard hardiebacker permabase and others the seams between the board need to be treated with 2 inch alkali resistant mesh tape. Pull out a big enough piece of tape to cover the entire gap then press the tape down on the gap.

Follow the manufacturer s instructions but this usually takes several days. Plan so the joints in the backerboard won t line up with the joints in the subfloor. You need to apply the tape while the thinset is still wet. The backerboard should completely cover the subfloor joints.

Once the mortar is dry you may begin to install the tile. No matter what you do don t forget the primer. If needed cut the backerboard to fit in small spaces or around obstructions. The way you treat your backer board seams is one of them.

Score the board with a utility knife then cut it using a jig saw with a carbide blade. Cut drywall to fill in between the existing wall or ceiling and the cement board. Step 3 more thinset.