How to Build a Stone Board for Under a Stove

Select a stone material that is approved by your local building code enforcement agency and recommended by the manufacturer of your stove and is UL (Underwriters Laboratory) listed for safety as a hearth pad material.

Review the owner’s manual for your stove model and follow the recommendations for building a hearth pad, in terms of materials, height and clearance space from the back and sides of the stove to combustible surfaces, such as walls, and from the front of the stove to flooring materials.

Select the area for building the stone board hearth pad. Corner locations next to an exterior wall make good choices because they provide a place to ventilate the stove directly to the outdoors.

Use a tape measure to get the dimensions of the stove (width and length). Add the minimum clearance requirements provided by your stove manufacturer to your measurements for the sides, back and front of the stove stand.

Run a tape measure from the nearest wall surface to the point where the stone board hearth pad should end on the floor.

Remove existing flooring material, such as carpeting or vinyl, in the area where the stone board hearth pad will be located. Use a utility blade and/or chisel to completely dislodge and remove the flooring material. Strip away the material all the way down to the subfloor material, which is typically concrete or plywood.

Use a carpenter’s pencil to draw an outline for the perimeter of the stone board hearth pad on the bare floor. Mark off the perimeter with masking tape.

Make a frame for the stone board hearth pad by cutting 2-by-4 pieces of lumber with a circular saw, according to your measurements. Connect the frame pieces with 2-inch wood nails.

Measure the finished frame and divide the width by 16. This will determine the number of boards you will need to cut to attach to the top of the frame. Cut the corresponding number of boards from 1-by-4 lumber.

Lay one board on the edge of the frame that butts against the wall, and one board on the edge that faces into the room. Place the remaining boards on top of the frame and space them out evenly. Attach all boards to the frame with 2-inch nails.

Cut cement backer board according to the dimensions for the top and sides of the stone board hearth pad. Nail the cement backer board to the lumber pieces on the top and to the side boards of the frame.

Measure the stone board hearth pad again to determine how many pieces of stone tile or stone slab you will need. Add 20 percent to your measurement to make sure you have enough material.

Cover the back side of the stone with mortar. Place the stones on top of the backer board. Allow 24 hours for drying to complete your stone board hearth pad installation.