CounterTops 2

Backerboard Splash

In the following section, an approach to the popular granite countertop with tile splash installation will be detailed. In this case, a black granite kitchen countertop system had already been installed by a previous tradesman.

 

 

 

     

As in any case when a previous trade has installed cabinetry or other structures that will receive tile work, the installer must determine that the work is satisfactory for the work to begin. In this case, the granite counters should be level and securely fastened all electrical work should be completed, and the areas should be free from other trades work during the tiling process.

     

The first step is to carefully measure the spaces for backerboard and tile. In this installation there were dry and wet areas. The wet area was behind and adjacent to the kitchen sink. In either case the existing granite was protected by masking with tape and heavy duty  paper. Then, the backerboard was cut to fit.

      

For the dry areas, the backerboard was installed directly against the existing wood framing.

 

 

 

During this process, the holes were cut for the electrical box and intercom system box. Note the close fitting of these holes. The backerboard is fastened with (minimum) 1-1/4” backerboard screws at 6” on-center throughout the field and all edges.

     

Note that there is a joint in the backerboard above and below the intercom box. This joint is a minimum of 1/8” and will be filled with thinset, taped with alkali resistant backerboard tape, and will be skim coated with thinset as flat as possible.

In these photos, another dry part of the installation receives its backerboard treatment.

 

 

 

Note the appropriate drill motor and screws used to fasten the panels. This photo details the proper grid pattern to fasten the panels. Be careful not to overdrive the screws in the panel. The installer should drive the screw flush with the surface of the panel if possible.

       

Note: Had this been a drywall installation, these fasteners would only follow the studs behind the drywall. It would be necessary, therefore, to measure and mark the location of the studs prior to the installation of the panels. Also, a longer screw would be necessary as the installer would need to penetrate the board and drywall and the stud behind a minimum of ¾”. Remember that the maximum spacing of studs for a backerboard installation is 16” on-center.

In the case of 1/4” backerboard, a 1-5/8” backerboard screw would be sufficient. If the chosen backerboard was ½”, the screw would need to be a minimum of 1-3/4”.

Dr’s Tip: If the correct length of backerboard screw for the project is unavailable, the installed should use a screw in the #10 class, the correct length, and it should be corrosion resistant. Many exterior deck screws meet these criteria.

In the case of the wet areas, 15lb roofing felt was placed against the framing lumber as a vapor barrier behind the backerboard panels. The panels were installed in the same manner as the others. Note that the panels are held up off the decks 1/8”-1/4”.

 

Once the joints have cured, the installer lays out the tile and makes his cuts if possible. This tile will be set with mastic, however, modified thinset would be fine too. The mastic is applied in a way very similar to thinset. The principle difference is the thickness of the setting bed. Follow the manufacturers recommendations for the size tile chosen.

 

Nevertheless, the mastic is first “keyed in” to the surface with the flat side of the trowel. Then an even setting bed is established with the notched side of the trowel held at a consistent angle.

 

 

 

       

The tile is then applied using the countertop as the lower course support. The tile is pressed into the fresh mastic or beaten in then aligned and spaced appropriately.

      

After the rest of the tile is set, the tile installation is grouted in the same manner described elsewhere in the Tile Doctor site. In a nutshell, the steps are mixing the grout per the manufacturers instructions, forcing a maximum amount of grout into the joints with a grout float, cutting off the excess with the float at an extreme angle, waiting the prescribed amount of initial cure time, tooling the joints with a nearly dry sponge so that the joints are smooth and uniform, and finally completing a final wipe with a nearly dry sponge. For the novice, it would be best to review the many photographic details within this site concerned with grouting.