Locate the flue for your fireplace. Drilling for the mantel should not be done within 12 inches on either side of the flue.
Measure the height for the mantel. It must be a minimum of 20 inches from the top of the fireplace opening or doors. Check local building or fire codes in case there are further restrictions in your area.
Hold the log mantel over the fireplace opening. Center the mantel over the fireplace.
Mark the location for two holes for mounting the mantel. Space the holes evenly to balance the mantel over the fireplace. Draw a straight line connecting the holes. Place a carpenter's level on the line and adjust to ensure that the holes are level.
Drill holes 4-inches deep at your marks using a ¾-inch masonry bit.
Insert 2 or 3 ounces of high-temperature silicone into the holes.
Place 10-inch reddy bolts into the holes.
Hold the log mantel in position. Have an assistant mark the position of the bolts on the flat side of the mantel.
Drill holes 6-inches deep using your marks on the flat side of the mantel using a ¾-inch wood bit.
Insert 2 to 3 ounces of high-temperature silicone into these holes.
Push the mantel onto the bolts. Hold the mantel in position until it is secure.