How to Build a Flush Hearth

Preparation

• 1

  Extend a tape measure 16 inches straight out from one corner of the fireplace opening and make a mark on the floor. Repeat on the other side of the opening.

• 2

  Draw a line connecting the two marks on the floor. Draw a line connecting each mark with the corner at the fireplace opening. This rectangle outlines your hearth. Measure the diagonals of the rectangle. The outline is square if the measurements match.

• 3

  Transfer the outline measurements to a sheet of backer board. Cut the sheet to fit with a circular saw.

• 4

  Place the backer board over the outline. Screw the backer board to the plywood. Place screws in the corners and in three rows across the board every 4 or 5 inches.

Layout

• 5

  Measure the fireplace opening. Find its center point. Place a tack or nail at its center. Wrap a string around the tack. Extend it straight out past the backer board and place another tack in the plywood. Wrap the string around the tack.

• 6

  Measure the hearth from front to back along the string line. Find the center point and make a mark on the backer board.

• 7

  Tack another string line, perpendicular to the first one, that passes over the center mark. This will divide the backer board into four sections.

• 8

  Fit the tiles over the backer board to determine the layout. Start at the front of the hearth at the center and work outward. Keep a space of about 1/8 of an inch between the tiles. Mark any tile that needs to be cut. Avoid leaving a tile less than 1 inch wide.

• 9

  Draw lines between the gaps in the tile.

• 10

  Place your tiles on a board in the same pattern as the layout. Remove any tiles that need cutting. Cut them to size with a tile cutter. Place them back on the board in their proper position.

• 11

  Use a chalk-line tool, which unrolls a cord that leaves a line of chalk, to outline the tile pattern. Ensure that the chalk covers the lines you made when laying out the tiles.

Application

• 12

  Spread a layer of thinset mortar over a portion of the backer board with a notched-edge trowel.

• 13

  Apply the tiles in the mortar guided by the chalk lines. Use 1/8-inch spacers to leave the appropriate gap between tiles. Start at the center and work your way out to the edges. Check each section for level when you finish.

• 14

  Finish a small area, then apply more mortar and continue. Thinset mortar has a working time of about a half hour.

• 15

  Wait 24 hours after tiling to apply the grout.