How to Cut Hardie Siding

Hardie board is a cement-board siding made from combining sand, cement, water and cellulose wood fibers. It is produced by James Hardie and revered by builders and homeowners as a durable, rot resistant, insect resistant alternative to wood and vinyl exterior siding.

Cutting Hardie board is just as easy as cutting wood or vinyl, yet the material is different and so new challenges arise. Hardie board is available in a variety of sizes, styles and thicknesses and there are different approaches to cutting each type.

1/4-inch Hardie Board

  1. Cutting 1/4-inch Hardie backer board is easily done almost the same way drywall is cut. Lay the Hardie board on a pallet or other raised surface.

  2. Position a metal square to make a straight line where you want the board cut.

  3. Take a utility knife and score the fiberglass mesh side of the board.

  4. Lift up part of the board to snap the fiberglass mesh and concrete board in a straight line.

1/2-inch Hardie Siding

  1. Using Hardie shears is the best way to cut 1/2-inch Hardie siding. Many brands of Hardie shears can be found at hardware and building materials stores. There are also attachments for connecting Hardie shear tools to drills for use in cutting holes in the Hardie siding.

  2. Hardie board can be cut with circular saws and regular cement, tile and steel cutting blades, but this produces a dangerous amount of dust. The Hardie shears are the most effective way to cut the siding while eliminating most dust.

  3. Use a square to draw straight line on board with pencil where cut is desired.

  4. Place board on sawing table or other cutting surface.

  5. Cut board with Hardie shears, circular saw or table saw.

Drilling Installation Holes

  1. Drilling holes is required for the installation of most Hardie siding. Screws cannot be installed right into the siding like wood. The Hardie board will crumble if you attempt to drill straight into the siding without first drilling pilot holes.

  2. Attach carbide tipped drill bit to drill.

  3. Use carbide tipped drill bits to drill hole through Hardie board.

  4. Be careful not to apply to much force, which could crack or crumble the panel.

  5. Insert screw into hole and attach siding to wood, studs or metal framing.

  6. Tip

    A shop vac can be used when cutting Hardie board with a circular or table saw to help mitigate the amount of dust that is released.


    Breathing the dust produced by cutting Hardie board is hazardous to your health. Protect your respiratory system by practicing the best dust-reducing methods while cutting Hardie board and by wearing effective particle-reducing masks and respirators.