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Building a Fireplace Mantel

Construction How-To, Construction How-To, Finish Carpentry, Fireplace, Mantels. Trim, Trim Carpentry January 3, 2007 Sonia

Nail the mantel shelf into the cleats along the back. Use a short level to double-check the mantel shelf from front to back and nail the crown into the mantel shelf along the sides and the front.

Measure and cut the mantel shelf, allowing for the reveal of the crown molding.

Use a router to shape the edges of the mantel shelf.

Scribe the mantel shelf to the wall. Use a power planer to shape along the scribe lines.

Mark the surface molding layout on the mantel legs.

Use a combo square to mark the reveal (spacing to the edge) of the surface molding along the arc. Mark the center of the arc. Layout the vertical edges of the two frames from center.

Cut and nail the surface molding in place. The miters at the arced horizontal piece will need a little extra attention. Use a couple of scraps to test the angles needed to make the connection or you can overlap the horizontal piece over the vertical and trace the angle. The new angle can be cut with a sharp utility knife.

Apply carpenter’s glue to the back of the bottom horizontal piece and bend it into place following the layout lines. When you like it, nail it.

After the stone surround is in place, mill a 1/4-inch-thick piece and bend it into place on the underside of the arc. Measure, cut and install base pieces or feet.

Add your favorite finish and the new mantle is complete.

Fasten the shelf from both above and below.

Add surface molding to suit your preference.

Mantel with surface molding complete and painted.

Add base molding “feet” for a finished look.


  • MDF
  • Table saw
  • Compressor
  • Nail gun(s)
  • Sander
  • Router
  • Level
  • Sliding compound miter saw
  • Crown molding
  • Bed molding
  • 1” molding for panels
  • Power planer
  • Carpenter’s glue