Solid Beam Fireplace Mantle (Mounting Info Included)

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Project by Durbs75 posted 10-27-2016 10:21 AM 3868 views 7 times favorited 4 comments Add to Favorites Watch

This mantle was hung on a rock fireplace wall. My client provided the beam and I hung it today! It is 6 inches by 6 inches by almost 70 inches long. The natural character is preserved and only lightly sanded to reveal some of the natural wood tone. It completes the space in my clients newly remodeled home!

I know there will be questions on how the mantle is mounted so I will show you how I do it in process pictures. The pictures are NOT from this mantle, but it shows how I mount ALL of my mantles. I locate the studs in the wall and insert two 3/8×6 inch or 8 inch lag bolts through the mounting board (into recessed holes so the bolt heads don’t stick out) and into the wall studs. The two rods are 3/4 inch black iron pipe and mounted with the floor brackets on the back side so they don’t move. To get the mortise on the back the beam, I use my router with a 3/4 straight bit and use my router edge guide to slowly take out all of the wood in the mortise. It takes a while, but it’s worth it in the end!! On larger beams I will use a 2 inch thick backer board and make the mortise about 2 1/4 inches deep and on smaller beams I will use a 1 1/2 backer board and make the mortise about 1 3/4 inches deep. The material for the backboard is typically yellow pine or oak.

It’s solid and works perfectly. Some clients want lag bolts through the front to add to the character of the beam and some don’t want hardware showing at all. Either way, the solid beams, weighing anywhere between 100 lbs to 300 lbs, this system will work and has worked!!!!

-- Carey Durbin, Marietta GA,

4 comments so far

View Randy_ATX's profile


881 posts in 3406 days

#1 posted 10-27-2016 02:27 PM

Beautiful work. Thanks for showing the details.

-- Randy -- Austin, TX by way of Northwest (Woodville), OH

View Jim Kuehl's profile

Jim Kuehl

16 posts in 2937 days

#2 posted 10-27-2016 05:25 PM

Thanks for sharing your process!!

When you don’t have exposed lag bolts, how do you attach the mantle to the backer board?

View Durbs75's profile


134 posts in 1580 days

#3 posted 10-27-2016 05:59 PM

Thank you all for your comments!

Jim Kuehl - I just use 2 inch long trim head screws. They are only about 1/8 inch round and hide very easily into the mantle. I screw on top and bottom of the mantle into the backboard. Since the backboard is generally 1 1/2 inches thick and the mortise is about 1 3/4 deep, I inset the screws about 1 inch from the back edges of the mantle and insert the screws there. Nice snug fit and the screws hide very well and blend into the character of the beams.

-- Carey Durbin, Marietta GA,

View Mean_Dean's profile


7057 posts in 4112 days

#4 posted 10-27-2016 10:44 PM

Very nice looking mantels you build—and thanks very much for showing your mounting method!

-- Dean -- "Don't give up the ship -- fight her 'till she sinks!" Capt James Lawrence USN

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