Fireplace Update

Today I want to share with you my fireplace update.  This is an easy DIY with a big impact.  When we moved into our builder grade home we had a little oak fireplace on a very large wall.  While I was thankful to have a fireplace, it was just too small.  I decided to paint it white many years ago, but it still looked a bit off to me.  Finally, after tackling a few other woodworking projects, I decided to update our fireplace.  Here it is today.

How to build an over-mantel.

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I’ll show you how to do this simple project, including materials and tools.



  • (3) Common Board – 1 x 8 x 6
  • (1) Common Board – 1 x 6 x 6
  • (3) Chair Rail 9/16 x 2-5/8 x 8
  • (1) Crown Molding 3-1/8″ x 3-1/2″ x  94-1/2″
  • (2) Panel Molding 5/16″ x 11/16″ x 8″

Measure & Cut

  1. Decide how wide you want your over-mantel to be.  I based my measurement on the width of the bottom of the mantel, mine is 5 feet long.  Then measure the height from the top of your mantel to the ceiling.  My measurement 4 feet by 2 and 3/4 inches.
  2. Cut your 1 x 8 x 6 to the width of your bottom mantel.  My width was 5 feet.  Repeat this cut for the top of your rectangle.
  3. Cut the remaining 1 x 6 x 6 to the height that works with your space.  My initial rectangle measures 3 feet by 6 and 1/2 inches tall.  Then I backed out the 14 1/2 inches for the top and bottom boards (each board is 7.25″ wide) which left my cut measurement at 2 feet 4 inches.  Cut your left and right boards to this measurement.
  4. Sand all four boards and attach them to your wall with a brad nailer.
  5. Cut the 1 x 6 to the same length (5 feet).  Sand it and attach it to the top of the rectangle.

How to build a DIY Fireplace Overmantle with white wood moldings.

Add Decorative Moldings

  1. Cut the chair rail molding on a 45 degree angle to match the outside height of your rectangle (my measurement was 3 feet 6 1/2 inches).
  2. Then cut the chair rail on a 45 degree angle to match the outside width of your rectangle (my measurement was 5 feet).
  3. Attach the chair rail to the outside of the rectangle with a brad nailer.
  4. Cut the panel molding on a 45 degree angle to match the inside height of your rectangle (my measurement was 2 feet 4 inches).
  5. Cut the panel molding on a 45 degree angle to match the inside width of your rectangle (my measurement was 3 feet 9 1/2 inches).
  6. Attach the panel molding to the inside front of the rectangle.
  7. Cut your crown molding upside down to match your 5″ top board.  Then cut your returns.  For more details on cutting crown molding see this post.
  8. Attach your crown molding with brad nails into the top cap.  Attach your returns with wood glue (hold in place with painters tape) or a glue gun.

Finishing Touches

  1. Use your putty knife to fill all holes and knots with wood filler.
  2. Use your caulk gun to fill and smooth all gaps.  Let the caulk dry.
  3. Prime all boards with Zinsser Cover Stain.  This keeps the knots from bleeding through your paint.
  4. Choose a trim paint that matches the trim in your home.  I use Behr Snowy Pine in Satin.


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How to build an over-mantel.
DIY Fireplace Update Over-mantel

Now step back and enjoy your beautiful new mantel.  This is seriously my favorite home project to date.  It really brought my living room together and made my fireplace the main focal point.  I hope you enjoy this fireplace update as much as I do!



    1. Hi Henry. Thank you for your question. I did paint the entire mantel and over-mantel with Behr Snowy Pine including the inside of the rectangle, which is just drywall.

  1. Laura, I’m reading your instructions and I need clarification on the 1 x 8 cutting. The top of rectangle and bottom of rectangle are cut the same at 5 ft. The sides of rectangle should also be 1×8’s cutting to our measurement, correct? You list to cut remaining 1×6’s.
    Also, we cannot use our drywall in the open space of rectangle and will be mounting a piece of 1/4 plywood over the drywall. Would you recommend that we only put plywood on center of rectangular or put it on the whole space?

    1. Hi Barb. I think I understand your question. The rectangle is all 1 X 8 boards. The 1 X 6 is over the rectangle to help balance and fill the vertical space. I added the 1X6 to mimic the look of the fireplace molding below. If you are going to add plywood to the center of the rectangle, I would only put it in the center, because the edges of the plywood are not smooth/finished. Also, you may want to move the panel molding into the center rectangle to cover the outside cut edges of the plywood. This will hide any uneven gaps for a perfect-looking finish. Hopefully, this helps.

  2. Hi Laura, we are just getting around to doing the fireplace makeover. We had to paint the room first. It appears that your space above your mantle is higher than ours. We have 8 ft ceilings and our space above mantle measures 40”height by 76”width. The width of the fireplace frame is 66”. Not sure how your design will look in our space. We will need to make adjustments to the measurements you provided. Your thoughts please? Thank you.

    1. Hi Barb. We have 9-foot ceilings, and I think it looks more “grand” with an overmantel. If you want an idea of how this will look with 8-foot ceilings, draw it up on paper first. Get all of your measurements worked out and then use painter’s tape to mask it off on the wall. This will give you an idea of what it will look like in your space before you purchase or cut any boards. If your walls are freshly painted, read the paint can for the curing time required before you put masking tape on the walls.

  3. Hi. Do you have a photo of the entire wall? I am getting ready to demo my FP and would love to see your picture frame molding on each side of the finished fireplace. Thanks!

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