How to Hide a Backer Board With Grout

Check the level of the screws in the backer board by running your finger over the surface of the material. The heads of the screws should be slightly lower than the surface of the backer board, creating small dimples. Use a screwdriver to tighten any raised screws so that all the screw heads are slightly deeper than the backer board surface.

Tape the joints between adjoining sheets of backer board with backer board tape. Taping the joints provides a continual surface area between individual sheets.

Mix up the grout in a drywall pan, following the instructions on the package. Allow the mixed grout to rest for the amount of time recommended on the label. Depending on your variety of grout, the resting time may take between 10 and 45 minutes.

Mix the grout again. Load one edge of a drywall trowel with the grout and apply the mixture to your backer board with a sweeping motion, spreading a thin layer of grout over the surface of the board. Apply another stroke beneath the first stroke, slightly overlapping the grout. Reload your trowel as necessary. Let the first coat of grout dry.

Apply a second coat of grout to the backer board in the same manner. Build up the grout to create a textured stucco appearance. Depending on your personal tastes, this may take between three and five coats of grout. Let the grout dry between each coat. Paint the grout to give your wall a finished look.