Mantel Construction

By Jeff | Jan. 15, 2013

With the tiling pretty much finished, we wanted to get the mantel ready to install. If you recall from our plan rendering, we’re going to have two columns on the sides, crown molding at the top, and shelving extending out to each wall.

New Fireplace

The first step was to cut the pieces to size at TechShop on the table saw. I decided to do miter cuts on the corners to make it look a little nicer, but I neglected to check one measurement. My original plan for the width of each column was going to be 9.5 inches, and so I bought “10 inch” wide board. I knew wooden boards were like hamburgers in that the measurement is actually a “pre-cook” measurement, but I didn’t realize that the board shrunk down to 9 1/4 inches! So I did some quick calculating and cut two strips I could join to the wider boards to get the required width so the columns fit over the existing brick.

A tip I learned from the people at TechShop is that when you’re making a 45 degree miter cut (to get a square corner), the distance from the beginning of the cut to the end is equal to the thickness of the board. This means that if the blade is set to bevel away from the fence like in the above picture, you’ll need to add the thickness of your board to your cut width. So if you have a 3/4″ board you want cut to a 5″ width, set your fence for 5 3/4 inches.

Once I got everything home, it was time to start cross-cutting (cutting across the grain) the pieces to the correct height. Now, you could take your tape measurer and measure the height of the fireplace, then all the other cuts, and then mark them out with the tape measurer on the piece and hope you weren’t off by a bit either time you measured.

Or you could just take your piece of wood, place it exactly where you want (use a level) and mark your height directly on the board once where you know it will be accurate. Use your square to make your cut line straight and square and then cut to fit. Personally, I’ve found the second method to be much quicker and more accurate (and you don’t have to remember that the height of the fireplace is 52 3/16 inches and the hearth height is 4 1/2 inches

Mantel Construction

Gluing everything together proved, as usual, harder than expected. The trick, I found to clamping the miter joint, was to attach both horizontal and vertical clamps and tighten them simultaneously so the pieces won’t shift. The biggest issue though was small imperfections in the straightness of the boards. Even though I picked the straightest ones the store had (a task in itself), it was just common board, which is nowhere near as straight (or expensive) as the poplar I used on for the table. So I had to bend the boards in place and clamp them until the glue set and kept them where they belonged. Some of the boards were straighter than others.

Mantel Construction

Another tip I learned to help straighten boards is to pinch clamps to keep the boards aligned like in the photo above. If you don’t have enough, you can add some regular clamps as well.

Mantel Construction

I cut the corner at the bottom out with a coping saw the first time. The second time, I tried using the circular saw with the speed square as a guide and it went much faster and was a cleaner and straighter cut. Since the shorter cut was such a narrow cut, I was worried that the circular saw would break the wood, so I still used the coping saw for that part.

Here’s an updated list of where we are in this ridiculous project.

  • Place initial layer of thin-set.
  • Tile fireplace.
  • Put on first layer of sealer.
  • Grout tile.
  • Put on second layer of sealer.
  • Make columns.
  • Paint mantel columns.
  • Install mantel columns.
  • Make shelves. (10% complete)
  • Paint shelves. (9% complete)
  • Install shelves.
  • Finish up mantel.