Recently we had to rebuild our built in fireplace and wanted a nice mantle. Custom mantles can cost quite a lot, so I designed this utilizing just a few pieces of wood AND the crown molding we also took out during the demolition. (The photo may appear to show a supported Mantle, however, the side pieces are for show and the mantle actually is a floating design with no other support.)
Had on hand: 1 ea. 6 foot long crown molding.
Pieces I purchased:
1 ea. 6 foot long 1 x 6
2 ea. 6 foot Wood stop molding
1 ea. 6 Foot 2 x 4
3 ea. 3 Inch Construction Screws
6 ea. 1.5 inch Construction Screws
5 ea. 2 inch finishing nails
4 ea. 4 inch Lag Bolts
4 ea. Washers
Step 1: Set the 2x4 / Add Skirting
The most important part of putting up a mantle is the leveling process. I had seen one or two 'DIY' sites where they showed how to 'shim' the top shelf level. If the 2.x 4 is leveled to begin with, you don't need to go through that.
I mounted the 2x4 on the wall with a 3" long contruction screw right in the center. Then with a level laid on top, I leveled the 2x4 and put in two more screws near either end, checking the level as I worked to keep it level.
Once this is done, I can now drill and put in the 4 lag screws and washers to hold the 2x4 in place knowing that the entire thing will be level without further work.
(Note, I knew the internal make up of this wall as I had just completed it, putting in extra wood to hold the mantle. See photo above which shows internal framework. If you are unsure of what is behind the drywall, use a stud finder or test with a long nail to be sure of mounting to wood.)
Using a miter saw, I then skirted the bottom of the 2x4 with the pine 'stop' putting the stop about 1/2 to 3/4 inch from the very bottom.
Step 2: Attach the Shelf
Before attaching the shelf, I laid it down face down and attached more of the pine stop. I used the distance measured at the top of the crown molding to set it at the proper distance. Then the shelf is ready to mount.
Using the short constructions screws, attach the shelf to the top of the 2x4 making sure it is centered. Run the screws through the top, into the center of the 2x4.
The photo above shows the mounted shelf from above and below. You can see the mounted pine stop molding in place ready for the crown molding.
The last step is to use a miter saw to cut the crown molding. Measure to meet the edges of the lower stop and attach using either finishing nails or long screws
NOTE: My shelf actually runs out in front of 2 pieces of 1x4 on the left and right. Rather than cutting a notch for these, I mounted a single 3/4 inch thick piece to match the height of the shelf. When complete, it will appears as if the shelf has been cut to accommodate the 1x4 on either side.
If you've never had to cut crown molding, you can use a miter box, or compound miter saw, using these measurements: (Place the top of the crown molding against the 'fence' or away from you. Set the Bevel at 33.85 degrees and set the Miter right at 31.62 degrees.
Step 3: Finalizing.
I've photo'd the side with the side crown molding removed to give you a better idea of how it is put together. You can also see the profile when it is completed.
Once this far, I sanded lightly, and then ran a bead of caulk along all joins.
When the caulk was dry, Primer and paint.
The finished look is both dramatic and unique.