How to Edge a Hearth

Measure the length of the hearth along the front of the piece, and the length of the two sides of the hearth with the tape measure. Measure the width of the trim piece that you’re using to edge the hearth as well.

Add the width of the trim to each of the side measurements and twice the trim width to the front measurement. Cut three strips of trim using a miter saw, two to match the adjusted side measurements, and one to match the adjusted length of the hearth along the front. Make certain each cut leaves a 45-degree angle in the end of the trim to create a frame around the hearth with two ends of the side pieces left at a 90-degree angle to fit against the wall at the side of the hearth, but both sides of the front piece containing the 45-degree angled cuts.

Test fit the trim surrounding the hearth. Make any adjustments necessary in the cut ends so that they fit together smoothly around the hearth, forming a three-sided frame.

Attach a tenoning jig to a table saw and position it so that you can attach the trim piece to the base of the jig and then push the mitered edge through the saw blade, cutting a seam through the rim center. Place each trim piece into the jig, tightening the jig using the wheel on the jig arm to hold the board in place with the mitered edge flat against the table saw surface. Adjust a 1/8-inch wide saw blade to a depth of 1/4 inch and then run each of the mitered trim ends over the blade, cutting a groove through each.

Cut a 1/2-inch wide wood strip that’s 1/8 inch in thickness to the length of the trim widths. Place glue on one side of the strip, and then place the strip into the groove cut on one of the mitered side hearth trim pieces. Place glue along the second side of the strip and then place it into the groove on the trim piece that runs along the front of the hearth, so that the two mitered angles meet to create a 90-degree bend in the trim. Repeat the process with the other two grooved ends of trim, creating a completed three-sided frame that fits around the hearth. A small sliver of the wood strip will remain outside each 90-degree angle.

Allow the glue to dry for an hour, and then cut off the protruding piece of wood within the grooves of the trim with a utility knife. Sand the surface smooth with fine-grit sandpaper.

Place a bead of wood glue along the bottom of the trim frame, and then place it around the hearth, pressing down on the trim to glue it to the surrounding floor. Place heavy books on top of the trim to hold it in place and allow the glue to set overnight before removing the books.