How to Lay Hardibacker

Hardibacker is a type of cement board commonly installed in high moisture areas.

Hardibacker has many different uses.Hardibacker has many different uses.
It is most often installed on floors in bathrooms. This material comes in 3-foot-by-5-foot pieces and is attached to the subfloor. Tile or other flooring material is then laid on top of the Hardibacker. The material will help protect the interior of any home from swelling, rot or other deterioration caused by water damage. It is easy to install with screws made specifically for it.

Set a level on the subfloor to verify that it is square and level. Inspect all of the sheathing to make sure there is no damage to any of the sheets. Brush off any dust and debris from the area with a broom and dust pan.

Measure the length and width of the floor in the room. Write down each number and multiply the two together to get the total square footage of the room. Divide the number by the square footage of a sheet of Hardibacker, which is 15, to figure how many sheets will be needed.

Spread thick dry-set mortar along the corner of the room where the first sheet will be installed. Spread it out with a trowel. Smooth the surface until it is even across. Set the first sheet of Hardibacker on top of the mortar at the corner leaving a gap of 1/8-inch from the edge of the wall for expansion.

Drive Hardibacker screws every 8 inches throughout the entire sheet. Keep the screws at least 2 inches from each corner of the Hardibacker and 3/4-inch from the edge. Set the fastener heads flush with the surface of the Hardibscker when driving them in place.

Spread out the mortar in the next spot and place the second piece of Hardibacker next to the first, leaving a gap of 1/8-inch between the two to allow for expansion. Install this piece and all of the remaining pieces in the same manner until reaching the end of the first side.

Measure and mark on the final piece of the first side where the cut will need to be made for it to fit. Line up a T-square along the mark. Score along the mark with a utility knife. Repeat the process until the board can be snapped in two. Install this piece just like the previous pieces were installed and continue in the same manner until the room is complete.

Things You Will Need

  • Level
  • Broom
  • Dust pan
  • Tape measure
  • Pencil
  • Mortar
  • Trowel
  • Hardibacker screws
  • Drill
  • Utility knife
  • T-square

About the Author

Alexander Callos began writing in 2005 for "The Lantern" at The Ohio State University and has written for various websites, including Bleacher Report, Top Ten Real Estate Deals and Columbus Sports. He has published articles for CBS Sports, SI.com and other websites. He graduated in 2007 from The Ohio State University with a bachelor's degree in public affairs journalism.