What To Put On Fireplace Mantel. Mark a level line on the box and fasten the crown molding to the top of the box with finish nails (image 4). Trim the top shims with a jigsaw (image 3).

Cut three poplar boards to size to 4.

There was no mantel…and i think all traditional fireplaces should have a mantel of some kind. Especially since the thickness of the picture frame hanging above it takes up part of that 7″. Depends on the size of the fireplace and whether the firebox is at floor level or raised. Learn how to give your dated fireplace a makeover with the addition of staircase posts, molding and a coat of fresh paint.