Hardibacker Board Installation

Hardibacker board is a fiber cement underlayment that was invented as an alternative to traditional drywall for bathrooms, kitchens and other areas that are constantly exposed to water. Because of this, Hardibacker board installation is more complicated than ordinary dry wall installation. However, Hardibacker board is better for protecting any home interior from swelling, rot, and other deterioration caused by water.

Uniquely Waterproof Tile Base

Hardibacker board is made chiefly of Portland cement, ground sand, cellulose fibers and selected additives. It contains no asbestos, gypsum, glass fibers, or formaldehyde. However, it does contain respirable crystalline silica. So, when cutting, grinding, or drilling Hardibacker board a dust mask must be worn.

As with any do-it-yourself project, it is important to follow the warning labels on this or any other products you are using in order to avoid injury. Hardibacker contains no asbestos, formaldehyde, gypsum or glass fiber, making it a safe material to work with and a safe material to install in your home, but you will be using power tools and the usual warnings and precautions apply.

As you may be able to imagine Hardibacker has a reputation built on safety, quality, durability and last but not least is its ten year guarantee from the manufacturer.

Tools Needed to Install

Among the tools and materials you will need for a project involving Hardibacker backer board are:

-A cutting tool for the Hardibacker backer boards such as a carbide tip scoring knife(recommend), circular saw with a carbide tip, or electrical Snapper Shear.
-Measuring tape
-Level
-Chalk line
-Carpenter’s square and a straight edge
-Pencil
-Safety glasses
-¼-inch notched trowel
-Hardibacker cement boards
-Thin set cement
-1¼-inch backer board screws
-Screw gun or drill with a Phillips head bit or a Phillips screw driver
-2-inch cement backer board tape

Countertop Installation

If you are covering countertops with tile, Hardibacker board will provide extra durability and resistance to moisture.

Countertop installation requires ¼” Hardibacker board, an application of thinset, and 3/4″ corrosion-resistant roofing nails. Hardibacker should be installed over a ½” plywood surface positioned across the cabinets.

Cut the Hardibacker to fit the countertop, making sure that the sheets of Hardibacker overlap any joints in the plywood. Apply a layer of thinset or dry-set mortar to the plywood and position the Hardibacker board so that there are 1/8” spaces between the board edges.

Fasten the board to the plywood with the roofing nails every 8″ over the entire surface. Keep the nails 3/8″ from the sheet edges and 2″ in from the sheet corners. Before laying the tile, use the same mortar you will be using for the tile to fill in the joints, and then tape off the mortar before laying the tile.

Floor Installation

For floor applications on an existing floor, make sure that the floor is level and structurally sound. Hardibacker may be installed over existing tile as long as it is not damaged. Make sure to repair any damage to the floor before proceeding with the installation, and then clear the floor of any other debris.

Cut and secure a foundation of ½” thick plywood to the floor with an appropriate adhesive. Cut the Hardibacker so that the joints are staggered from those of the plywood and so that no four corners of Hardibacker board meet up in the same place. Keep a 1/8” space between the board edges. Keep the same gap between the boards and the cabinets and walls.

Apply a layer of thinset or dry-set mortar to the plywood. Firmly place the Hardibacker board into the wet mortar. To fasten the Hardibacker board to the plywood, use 1-1/4″ long corrosion-resistant roofing nails every 8″ over the entire surface.

Keep the nails 3/8″ from the sheet edges and 2″ in from the sheet corners. Before laying the tile, use the same mortar you will use for the tile to fill in the joints, tape off the mortar, and level.

Other Uses

Hardibacker may be used for walls by following the floor installation directions and by substituting the word “joists” or “structure” for plywood. Hardibacker can also be used in showers and fireplaces and also laid over existing vinyl or linoleum tile.

It cannot be used outdoors or laid directly on concrete. Always make sure to read the directions on the products you will be fastening to Hardibacker boards. Different kinds of stone and tile have unique characteristics that must be taken into consideration during installation.