How to Build a DIY Fireplace

I have been dreaming up this project for what feels like so long!

We have a larger master bedroom and during the chilly winter months it just never seemed to actually warm up! About a year ago we started using an electric fireplace unit and it made such a big difference. So while the room was warmer in temperature, I knew we could build a surround that would make the room feel even more cozy!

Materials:

8 – 8’ 2×4
1 – 8’ 1” x 10” board
1 – 8’ 1” x 12” board
2 – 8’ 5/4” x 6” boards
1 – 8’ 1” x 6” board
1 – 4’ x 8’ Hardboard panel
Mantel (2 – 8’ 1”x 6” boards)

Tools:

Drill
Drill bits
Miter Saw
Nail Gun
Nails
Circular Saw
Multi-tool
2 1/2 inch wood screws
3 inch wood screws
Pocket Hole Jig
2 1/2” pocket hold screws
Clamps
Wood Filler
Paint Supplies (roller, pan, paint brush)

Part One: Build Hearth

The first part of this build was the hearth frame. I used 2×4 lumbar to create the frame and then used 1×10’s and 1×12’s to cover the frame.

Cut List:

6 – 2×4 @ 9 1/4”
6 – 2×4 @ 7 1/2″
4 – 2×4 @ 31 5/8″
1 – 1×10 @ 69 1/8”
2 – 1×10 @ 10 5/8”
1 – 1×12 @ 69 1/8”

For the hearth frame: start by making the three smaller box frames.

Drill four pilot holes into each of the 9 1/4″ boards. Two at the top end and two at the bottom end. Then connect the 9 1/4” boards to the edges of the 7 1/2” boards. Repeat for the bottom 7 1/2” board to create a square.

Repeat two additional times until you have 3 of the smaller frame boxes.

Next, drill pocket holes into each end of the 31 5/8” 2×4 boards. You will use these holes to attach the frame boxes together.

With the pocket holes drilled, then attach the 31 5/8” 2x4s between two of the small frame boxes at the front and back.

These 4 boards should be attached at the top of the frame boxes.

Set the hearth frame into place and then secure to the wall into the studs.

With the hearth frame secured, you can begin to cover the frame with the 1×10’s and 1×12’s.

To attach the 1-bys to the frame I just used my brad nailer with 1 1/2” nails. I started by attaching the 1x10s to the sides and front. Then I placed the 1×12 on the top of the frame and attached it.

Part Two: Build the Upper Frame

Cut List:

3 – 2×4 @ 4 1/2”
4 – 2×4 @ 18″
3 – 2×4 @ 11 1/4″
2 – 2×4 @ 36 1/2”
2 – 2×4 @ 64 1/2”
10 – 2×4 blocks @ 1/2”
2 – 2×4 @ 67 1/2”

For the upper build I started with the most important part! The frame that would sit around the actual insert. (Black section in graphic).

STEP 1: Using one 2x4s cut at 64 1/2” as the bottom, attach the four (4) 18” 2x4s from the outside of the bottom 2×4. I drilled pilot holes and then attached using 2 1/2” wood screws. The space between the center two 18” 2x4s is 41 1/2 inches, which is the space needed to fit the fireplace unit. The outer two 18” 2x4s are set 7” out from the center 2x4s. The outer 2x4s are more for attaching the cover boards.

STEP 2: After building the lower part of inner framing, I then attached the spacer boards (dark blue in the graphic) to the bottom of the 64 1/2” 2×4. The lower spacing boards are 4 1/2” tall, this is just the lift amount I wanted the fireplace unit to sit off of the hearth. All of the spacing boards are attached directly through the 64 1/2” 2x4s using a pilot hole and 2 1/2 inch screws.

STEP 3: Next, I attached the 36 1/2” 2×4 boards to the edge of the lower 64 1/2” 2×4. (As pictured in red in Step 3 graphic).

STEP 4: With the lower part of the framing complete I then grabbed the second 64 1/2” 2×4 and the three (3) 11 1/4” 2x4s. I attached the three 11 1/4” 2x4s on center to the 64 1/2” 2×4 (as pictured in Step 4 graphic).

STEP 5: With both the upper part and lower part of the frame built, I then needed to work on creating the depth.

I cut ten (10) 1/2” 2×4 blocks and attached these to the backside of the spacing boards (blue – 11 1/4” & 4 1/4”) and the edge boards (red – 36 1/2”)

STEP 6: After attaching the 1/2” blocks, I then attached the two (2) 67 1/2” 2x4s to the back of the lower frame part through the 1/2 blocks.

At the top it was attached into only the edge boards, at the bottom I attached it to the spacing boards and the edge boards.

From here, move your frame into place and set on top of the hearth. Attach the frame through the 67 1/2” 2x4s directly into the wall studs. I used 3” wood screws to attach the frame for a secure and sturdy hold.

STEP 7: Set the fireplace insert into the lower frame and attach to the center 18” 2x4s.

With the fireplace set in place, now set the upper part of the frame and attach downward into the 18” 2x4s. Then, attached through the 1/2” blocks using and angled drive into the 67 1/2” 2×4 that is already attached to the wall studs.

Part Three: Covering the Upper Frame

Okay! You made it through the hardest part!!

Next is covering the framing to really make this fireplace come to life!

I started first by cutting out the hardboard frame that would surround the fireplace unit. I used a a full 4’x8’ sheet of hard board to cut this out.

I used my circular saw to cut the panel down to size. The total outer measurement of the panel is 58 1/4” x 31 1/8”. Then I used my multi tool to cut the inner section out. The inner section is 43 1/4” x 18 3/8”.

The bottom section is 6 1/2” and the top section is 7 1/8”. Then centered, leaving 7 3/8” on either side.

You can really finish the hardboard how ever you prefer! I used a limewash finishlimewash finish on the hardboard, but you could paint it, or us a backsplash tile, or a peel and stick tile!

If you want to try limewashing, you can find detailed how to here!

Cut List:

2 – 5/4” x 6” @ 31”

1 – 5/4” x 6” @ 69 1/8

2 – 1” x 6” @ 31”

2 – 1” x 6” @ 5 3/4”

Next is adding the faux columns. I wanted the fireplace to appear inset and wanted to create a faux column looking surround.

To do this I use 5/4” x 6” boards on the front and 1” x 6” boards on the sides.

I first attached the 1” x 6” x 31” boards to the 5/4” x 6” x 31” boards. The 1” boards side inset behind the 5/4” boards. Attaching the corners together first allow me to then slide them into place between the window trim.

Then I attached the top 5/4” x 6” x 69 18” board on top of the 31” boards.

Lastly, I slide the 1” x 6” x 5 3/4” boards along the side set behind the 5/4” board.

All the faux column boards are attached directly into the frame with my brad nailer and 1 1/4” nails.

Part Four: Finishing

There are so many options to finish your fireplace! You could stain the wood, paint the wood, or do a combo of both!

I decided to paint the hearth, faux columns and up the wall all in the same color. For me it just made such a statement in the space and brought in such a cozy vibe for our bedroom.

This is the color SW Secret Garden, however, after the first coat I did end up mixing in the smallest amount of SW Iron Ore to darken the color just a bit.

The last part was adding the mantel. The current mantel is a temporary one, just using 1” x 6” boards. The mantel is 8” deep and 70” wide. This will be the same measurement for our permanent mantel, but the permanent mantel will be 2” wide and will be a solid piece of wood!