Build your own mantel: the instructions

September 27, 2011

So you want to build your own mantel? Yesterday I shared the mantel project I tackled this weekend and asked your opinion on what we should do to fill the space… A lot of you have voted already, but if you haven’t, you still have until Wednesday at midnight {CST} to cast your vote!

It occurred to me, halfway through the building process that, as a good blogger, I should have been taking pictures every step of the way. Oops! I was too into building and getting this thing done before the hubby came home that I just decided against it. Then I had some requests for the step-by-step, so thanks to Google Sketchup, I bring you the tutorial!

I am, by no means declaring myself an expert here, I just went with what I thought looked good for my space.

First things first, I went to Lowe’s and purchased the following:

  • 1 – 1x4x8′ {I had useable scraps at home, so if you’re starting fresh, you’ll need 2} premium lumber {not white board}
  • 2 – 1x3x8′ premium lumber
  • 7 – 8′ long, 1-1/4″ lattice {found on the trim aisle}
  • 1 – 1x12x6′ white wood
  • 1 – 4×8 sheet 3/4″ MDF cut to the dimensions below {you can use wood if you’re staining}

You may also need:

  • Primer, paint/stain, & Polycrylic {I had all on hand}
  • 2×4 scraps
  • wood glue
  • finishing nails/nailer {I used a compressor/finish nailer with 1.5″ & 2″ nails}
  • Drill
  • Hole saw {to cut holes for cords}
  • 1-5/8″ & 2-1/2″ screws {I used drywall screws}
  • Caulk/wood filler
  • Sander/sanding paper
  • Painters tape
  • Pandora station

Ok, so I threw that last one in there for good measure. It really cut down on costs by cutting my bigger boards from a 4×8 sheet, plus, the guys at Lowe’s will make the cuts at no cost to you, so when you get home, you don’t have to cut the big stuff! Plus, they can measure it once and set it so you’ll be sure to have straight, uniform cuts. With the cuts, you’re basically making 1×12’s, 1×10’s and one 1×4.

The first thing I did when I got home was build to two main boxes that make up the base. To do this I took my 47-1/4″ 1×10’s {two per box} and my 30″, 1×12’s.

Using wood glue and my nail gun, nailed the face of the box to the sides, being sure to use my square to check the corners while keeping the bottom and edges flush. After I had secured the front, I cut a 2×4 into two pieces 10″ long per box and wedged them in the backside, nailing as I went and keeping them flush with the back.

This will further ensure the boxes are square, and beef up the strength of the boxes.

Next, I placed the boxes on the wall where they would go, and measured out their exact placement on the wall for the mantel to be centered. My mantel base is 48″ wide so I was sure to place the boxes at 48″ to the outside edges apart. When I had the boxes placed, I marked the insides on the wall with a pencil and moved the boxes out of the way.

I placed some more 2×4 scraps flush with the inside edges of the boxes on the wall and drilled them in with 2-1/2″ drywall screws. This is where you would want to try and hit studs because this is your main support for keeping the mantel attached to the wall. Lucky for me, our house was built in the early 40s and has shiplap behind all of the walls, seen here.

Once you have the bracing attached to the wall, slide your boxes into place and use some 1-5/8″ drywall screws through the sides of the boxes into the 2×4’s. One thing to make sure of here is to check for things to be level, both vertically and horizontally. I decided not to cut out the baseboards where the mantel would attach to the wall so I needed to shim the top of the boxes off the wall about 1/4″ {the same depth as the baseboards} to keep them level vertically. This left me with a gap, but that gap would be covered by the trim later on.

Next, attach the 48″ 1×12 to the face, using glue and nails. I actually shimmed mine up about 1.5″ from the top of the 30″ pieces. I made it a little difficult for myself, but it worked out in the end. The gap {or seam, if you didn’t shim yours up} will be covered by trim. If you don’t shim yours up, you might have to adjust some of your measurements of placements for the trim, or start with shorter sides to your boxes.

Once that piece is nailed into place, grab your 48″ 1×4 {cut from the sheet}, and place it on top of the 1×12 you just attached.

For the underside, you’ll need to verify measurements and cut your 1×12 white wood board to fit, mine was 25″ long. I attached more 2×4 scraps to the insides of the boxes at the height I wanted my underside piece at {30″ for me}, then nailed in the piece from below into the bracing. Be sure to drill a hole in the piece for the cables.

Next, start measuring and cutting your 1×3 trim, mitering all of the corners.

The next step is attaching the top. I was only going to make mine with the 1x12x54 I had cut and 1×4 trim, but my cable box is a little too big for that scenario. Thankfully I had a 1×2 scrap laying around that I was able to use to extend it just a little farther.

Glue and nail down the boards, making sure to center them.

Next, measure, cut, and attach the 1×4 trim {with mitered corners} along the edges of the mantel top. Make everything flush with the top.

Attach the base trim, for me it was simple 1×4’s because all of our baseboards are that, yours could be a little more ornate. Making the base boards match will give you that ultimate built-in look.

Now measure and attach the lattice trim on the sides. Make everything flush up with the wall and the front face of the mantel. I also trimmed out the inside of the “fireplace” at this time.

Next, attach the lattice trim to the face of the mantel, this will cover up all raw edges. It is not shown here, but all vertical end pieces should be attached first, then the horizontal ones added second. The raw edges of the wood should but up into something so they’re not visible.

Finally, use wood filler to fill all nail holes and imperfections, then sand your little heart out to make things smooth. Once you sanded and wiped down, prime, paint and seal to protect your finish!

Go build something!


  1. Grandma C says:

    You give very clear and concise directions. I might even be able to build one but I don’t have your perfectionist gene. Love Grandma C

    September 27th, 2011 at 12:26 pm

  2. DAD says:

    Where is the aquarium?

    September 27th, 2011 at 3:09 pm

Leave a comment