DIY Faux Wood Beam Fireplace Mantel

After searching for wood beams for my fireplace online and shopping at a local reclaimed wood store, I found the best option was to build my own faux wood beam, both financially and aesthetically. Most beams stick out and attach to the face or sit on top the fireplace. With limited amount of space on top because of our TV, and limited amount of space in front of the fireplace because our TV pulls down, I needed the wood to wrap around the fireplace. I knew I wanted the beam to look realistic. With a lot of DIY beam instructions I found online you could see the edges where the pieces of wood met up. I also wanted the wood to be a little rough for a more rustic look. I chose a rough-sawn cedar wood for this reason. I hope you enjoy this tutorial and find it helpful. Of course, please reach out with any questions you have.


wood (rough-sawn cedar or desired wood choice)

miter saw

table saw


brad nailer gun

1 1/2″ brad nails

wood glue

mouse sander

stainable wood putty

putty knife

wood stain

rubber gloves

white paint



tape measure

Step 1 

Measure the distance across the fireplace and the depth. Consider the thickness of wood when measuring. Be sure to give yourself a little wiggle room for cutting. I gave myself an extra two inches. You can aways trim more off, but if you cut it too short you will have to purchase a new piece of wood and start over.

Step 2 

For the short ends you can use a miter saw. Cut a 45º angle. For the length you will need a table saw rip it with a beveled edge at a 45º angle. Cut opposite directions of 45º angles for the each of the long pieces of wood. Take your time and move at a slow and steady pace. It would  be helpful to use grips if you have them. If you are not used to using a table saw, they are not very forgiving and you have to have firm grip on the wood. I would suggest practicing the cut with a scrap piece of wood first.

Step 3

Attach the front face of the beam to the top of the beam with your nail gun.

Step 5 

Add wood glue to inside of wood beam for added support. Push glue down into crack. Let dry. Repeat this step for side pieces.

Step 6 

Chisel edges of beam for a more rustic look.

Step 7

Add stainable wood putty to cracks, smooth with putty knife.

Step 8

Sand the dried putty with a mouse sander until smooth. I used 180 grit sand paper.

Step 9

To give the beam a bit more of a rustic look you can rough it up a bit. Chains give a great natural rustic look. Give the wood a few gentle whacks randomly throughout the beam.

Step 10

Apply wood stain with a rag. Rub in continuous strokes along wood grain. I used Minwax’s “Provincial” stain.

Step 11 

For a distressed faded wood look add a white wash. Lightly dip tip of brush into white paint and brush onto wood. Next, dip the brush in water and spread out the paint on the wood.

Step 12

Rub paint in with rag. Rub off paint until you get the desired color. Work in small sections, as you don’t want the paint to dry.

Step 13 

Attach the beam to fireplace. You can adhere it to the bricks with liquid nail.

Follow link to learn how I added a german smear to our fireplace.

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