Fake Fireplace Mantel from Pine Boards

Lay out the top board and the two legs and join them into the basic upside-down U. If you have a pocket hole jig, attach them from the back so no fasteners show on the face.

Add the front face pieces to the legs and top. If you're using a pocket hole jig, read the crown step first — you want to know where the crown lands before you commit the position of the 1x4 reveal board.

Add the 1x3s to the back edges to give the mantel real depth so it projects off the wall like an architectural element instead of a flat board. Block between the 1x3s with short 1x3 pieces (~7-3/4") for rigidity.

Before fixing the upper reveal board (the 1x4), lay your crown moulding in place and adjust the 1x4's position so that 2-1/2" is revealed on the front below the crown, matching the 1x3 reveal. Getting this offset right is what makes the crown sit correctly later.

For the thin decorative face pieces, glue is the answer — nails split them out at the edges. Clamp and let the glue set rather than forcing a fastener where the wood is too narrow to take one.

Cut the crown moulding to fit, mitering around the outside corners. This is the visible payoff cut — dry-fit and shave the miters until the corners close with no gap before you glue and pin them.

If you want the inset-square detail, cut the edge moulding to fit and glue it in place on the front panel.

Fill nail holes, caulk the moulding seams, sand, and paint. A mantel is nearly always painted — a semi-gloss trim paint gives it the crisp architectural look.