How to Adjust an Antique Fireplace Mantel to Fit

Adjusting the Height

• 1

  If the sides of the mantel, the "legs," are uniform all the way down, use a circular saw to remove part of the bottom of the legs on each side.

• 2

  Remove any decorative molding at the bottom of the legs before you cut them. Remove the molding by prying it loose with a cold chisel and hammer before you shorten the legs. Reattach the molding with finish nails after the legs have been shortened.

• 3

  Add a block of trim to the bottom of legs that are too short. You may need to shorten the legs slightly before you add the trim to achieve the desired height. You may also replace any trim at the bottom of the legs with a wider size. Many types of rectangular trim molding pieces are available from lumberyards.

• 4

  Spackle the nail holes and cracks and touch up the paint on a painted mantel. Sand and touch up the finish on an unpainted mantel.

Adjusting the Width

• 5

  Remove the legs and move them farther apart or closer together, if the width of the top of the mantel allows. This is the easiest way to adjust the width of a mantel opening.

• 6

  Remove the legs and trim them vertically to create a larger opening. Trim both sides of symmetrical legs to keep their uniform appearance. You may be able to carefully trim the inside of the legs without removing them from the mantel. If there is a piece of molding on the outside of the legs, it can be removed to make the legs narrower.

• 7

  Create a smaller fireplace surround in a large mantelpiece by painting the wall inside the mantel to match the mantel. Add trim molding to cover any gaps. If the distance between the mantel and the fireplace is wide, add additional molding to the wall. This molding should repeat the design of the mantel. This will unify the look of the fireplace. A row of flat molding around the firebox is a nice touch for this type of installation.

• 8

  Enlarge a mantel with a new top when the size of the firebox opening is correct, but the overall size of the mantle is too small. Place a board on top of the mantel and add an extra row of trim molding around the edge of the board.