Thank you for your patience. I know it has been a long time coming, but we finally figured out how to build a floating fireplace mantle, and we’d love to show you how we did it!
We still need to finish filling the nail holes and some touch up paint, but for the most part, it’s show-off-able.
Want to see how you can make one of your own? Watch our video!
It was surprisingly hard to find instructions online to build a floating mantle. We actually didn’t find any that looked like what I wanted, so we got creative and made things up as we went along.
Me: All I want is a chunky mantle that is classic and substantial, but not too simple-looking that fits well with the southern farmhouse feel of our home but isn’t distressed. And I need it to float in mid air and be sturdy enough to hold heavy stuff like Christmas stockings and giant candle sticks and not come crashing down on the kids.
Eddie: Oh is that all?
We went to Home Depot and I started taking out boards and holding them up to each other like a 10 foot long jigsaw puzzle until I figured out what I wanted. Then Eddie got to work with the “float in mid air” part.
First we used lag bolts to hang a 4×4 securely on the wall, into three studs. This is what we attached all of the painted pieces to. If you are going to use pressure treated wood for this step, make sure you use galvanized or stainless steel screws, bolts, and nails for the whole project.We left a 3/4″ gap on each side of the 4×4, so that our mantle would be flush with the wall when we covered it up.
Then we used our handy dandy HomeRight paint sprayer and painted the pieces we were using to build the mantle. Besides the 4×4, we only used four boards from the hardware store to build our mantle. However, we still need to go back for one additional board to cover the bottom.
We used:
a 1×10″ board (for the top)
a 1 x 6″ board (for the “skirt”)
a piece of decorative edge trim (for the top)
a piece of crown molding
Since our fireplace is an unusual size and yours is probably different, I’m not going to give you specific measurements, but I’m sure you can figure it out. It was a pretty simple process once the engineer (my husband, who really is an engineer) was confident we had a safe way to build it. First Eddie attached the 1×10 to the top of the 4×4, making sure it was level. 
Then we cut the 1×6 and used it to make a “skirt” around the front and sides of the 4×4. 
I guess if you were looking for a really simple mantle, at this point you could be done.
But we wanted to fancy it up a bit, so we added a decorative edge around the 1×10 on the top. 
Then we put crown molding around the “skirt” as well.
All that’s left is to fill in the nail holes, caulk, and touch up paint. (We are planning to cut a piece of plywood to cover up the bottom as well.)
We put a baby bumper around the hearth to soften the sharp edges for the kiddos.
If you’re interested in how we did the rest of this fireplace wall, check out these posts. The stone hearth and the AirStone wall are also D-I-Y projects!
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Installing the flagstone hearth
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Looks amazing. I love all the molding. Great job!
Thanks, Lisa! We certainly couldn’t have done this project without you. I’m so happy you suggested the Airstone!
Having seen this in-person, I can attest that it is GORGEOUS. And that you wow me–always. xo.
Love this guide! So clear and love the beautiful pictures. I was trying to figure out how to build the entire shelf but this post helped me with the shelf immensely! If anybody’s looking for the entire mantel surround, you can check out the other one I used:
http://www.portablefireplace.com/blog/how-to-build-fireplace-mantel-from-scratch/
The photo’s aren’t as high quality but the information is there. I’d refer back to Stephanie’s post for the mantel shelf. Oh, and the video is quite helpful as well. Thanks Steph!! <3
Thank you, Cheryl!
This looks great. We’re looking at replicating this exactly! One question, did you predrill the holes for the lag bolts?
I don’t think so. If I recall correctly, we used an impact driver to drive them straight into the studs.
UPDATE: My husband has corrected me and says that he did pre-drill them. I apologize for any confusion!
I finally got the mantle I wanted thanks to this post. Our fireplace is a stone brick from floor to ceiling so attaching the 4th was difficult but done. So pleased with how it turned out. Thank you
I am so happy to hear that! Thank you for coming back to let me know it worked for you!
Where did you get your edge trim for the shelf portion??
All of our trim came from Home Depot.
What size lag Bolts? What did you use to make holes in 4×4?
Thanks
My husband handled that part of the project. I emailed him at work today with your question, and this was his reply, I hope it helps!
“I think we used lag bolts that were 5″ or 5 1/2″. This ensured a minimum of 2 1/2″ of embedment into the stud. Need to pre-drill or you risk splitting the studs. I just used a spade bit to make the holes to recess the lag bolt heads that was big enough to fit the socket around the head. Can’t remember the exact size. Probably 1 1/2″ would do it. It’s ok it they are a little too wide – it won’t hurt anything.”