Unlike most marble mantels, this one was too thin to support the electric firebox in the middle. The electric firebox was 12 inches wide and the mantel was 5 inches.

Steps

1: Measure the area for the marble fireplace surround. Draw exact diagrams on graph paper to demonstrate height, width, marble placement, and overall pattern required. Calculate the precise amount of marble needed to finish the job. More is not better here.

2. Ensure that all surfaces are flat and level. Fill up any hollows or uneven sections with thinset compound. Apply stress fracture material where materials differ. Stress fracture material allows for varying expansion rates of materials and prevents cracks when heated. When applying thinset compound, make absolutely sure all surfaces are sterile and free of defects.

3. Start by attaching a temporary wood strip to the marble fireplace surround. Work down and across. Dry fit stone into place using double sided masking tape to determine if any parts need to be trimmed. The marble cutting saw can be used for this. When the design is finished, it’s ready to set the marble. Use cardboard to level the marble.

4. Use a trowel to apply thinset to the marble to seal the stress fracture membrane. A rubber mallet gently coaxes marbles into position. Marble can be held in place with wood wedges, strong masking tape, or heavy furniture. Allow 24 hours for the stone to fully adhere to the surroundings.

5. Seal marble and grout using manufacturer’s sealant. When the grout is dry, clean it with a dry cloth, then clean it well.