Things You'll Need
Carbide-edged scoring knife
Drywall square or metal straightedge
Thin-set mortar (optional)
1/4-inch notched trowel (optional)
Electric drill & screwdriver bit
Fiberglass-webbed joint tape
Hardiebacker, sometimes called "Hardie board," refers to a cement-based panel manufactured by the James Hardie Co. that is used as the substrate for ceramic and stone tile installations. Hardie board is installed over a plywood or OSB base for floors, counter tops or any horizontal surface and applied to vertical wall framing over water-resistant drywall. Proper installation of Hardie board follows a basic procedure that ensures a secure, stable surface to support the tile.
Inspect the surface that the Hardie board is to be applied to. Check that all the nail or screw heads are driven flush to the surface.
Prepare an amount of thin-set mortar mix, if applicable, according the manufacturer's directions. Note: Mortar is not required on wall installations and you can proceed to Step 3.
Lay out the first sheet of Hardie board. Measure the surface dimensions where it is to be installed and mark any necessary cuts on the Hardie board surface. In addition, for wall installations, cut the length of the sheet so that the end joint, if required, splits on the vertical center line of a wall stud.
Score the cut lines marked in Step 3 to cut the Hardie board. Align the blade of a drywall square or other metal straightedge with the cut line and use a carbide-edged knife to firmly score the line. After scoring, press down on one side of the scored line while lifting up on the outer edge of the panel to snap the Hardie board at the cut line.
Spread a layer of thin-set mortar over the horizontal surface, if applicable, using a notched tile trowel. For wall installation, proceed to Step 6.
Position the piece of Hardie board onto the thin-set mortar or against the wall and attach it to the surface using backer-board screws. Spacing for the screws should be approximately 6 to 8 inches across the piece and 2 to 3 inches from the edges.
Complete the installation of the Hardie board panels by repeating Steps 4 through 6, as applicable.
Apply fiberglass tape to all the seams where the Hardie board panels meet to complete the substrate preparation. Span each seam evenly with the tape. The Hardie board is ready for tile application.