DIY Fireplace Part 2 – The Basic Structure Finished

Last Updated on December 24, 2015 by Kristi Linauer

I didn’t get as much done on my fireplace yesterday as I had hoped, but I was able to get the basic structure completed. Here’s how the fireplace looks now that the basics are complete.

If you missed Part 1 of this project, you can click here to see it.

Now let me emphasize that this fireplace is electric.  There will be no actual flames (which is why nothing has to actually be fireproof), and all heat generated is blown out the front through the vent at the bottom of the electric fire insert.  So no heat at all is blown into or gathered inside the box.

Of course, it’s very rough at this point. There’s still lots of sanding, wood filling, trimming, caulking, priming, painting, tiling, and grouting to do. Plus, I still need a mantel.  But it’ll get there!

But let’s back up a bit. When I left you yesterday, the fireplace looked like this…

Now obviously I wasn’t just going to set the insert on the floor, and have the floor, wall, and the inside of the fireplace showing like that, right?  Of course not!  🙂  I still needed to build the whole interior that included the fire box.

To do so, I started with my two 11.5″ x 24″ pieces, and my two 11.5″ x 23.5″ pieces, and glued and nailed them together to form box that was 22″ x 24″ in the inside.  (My electric insert is 20″ wide, so I wanted my fire box to be 22″ wide and 24″ high.)

(Note: Most real fire boxes are angled in towards the back, but I would need a table saw to make those kinds of cuts. So I just went with a box with 90-degree angles. Hopefully once it’s all painted and finished, people won’t even notice my lack of angled sides. 😀 )

Once that box was built, I took my 36″ x 39″ piece of MDF and arranged the box on top of it like I wanted it.  Then I used a pencil to mark the inside edges of the box onto the piece of MDF.

Using those lines as my guide, I cut out the center using my jigsaw.  Since I couldn’t start on an edge, I started by drilling a 1/2-inch hole close to the line (inside the box), and then using that hole as the starting point for my jigsaw blade.

And then I glued and nailed this frame onto the box.  (Sorry!  No picture of that step.)

With the frame attached to the box, I set the fire box upright leaving the frame hanging over the edge of my work surface (i.e., my front porch 😀 ) so that it would sit upright completely.  Then I cut a piece of plywood to fit over the back of the fire box, and just leaned it into place.  Then with my fireplace insert inside the box, I marked where the hole needed to be for the electrical cord and plug.

Using my jigsaw, I cut away the rectangle for the electrical cord, and then attached the plywood backing onto the firebox using glue and a nail gun.

The last thing I needed to do on the fire box insert was add some legs to the back so that it would stand on its own. And since they would be completely hidden, they didn’t have to be pretty at all.  I measured and cut four pieces of 2″ x 4″ lumber, and glued and screwed two pieces together to form each leg.  Then I glued and nailed those into place.  I nailed them from the inside of the firebox since the electric insert would cover those holes.

And with that, the fire box insert was finished!

Then I just needed to do one more thing before placing the fire box insert into the fireplace box that I showed you yesterday.

Using 1″ x 2″ lumber, I cut, glued, and nailed a “frame” around the inside edge of the opening.  I did this on the left, right, and top of the opening.  The purpose of this frame is to give the fireplace some dimension.

And then with that frame in place, I was ready to put the fire box insert into place.  You can see here how that frame I just created gives some nice dimension to the fire box insert.

And here’s what the whole thing looks like at this point.

Can you envision it now?  Here’s my drawing to help you envision how this whole thing will come together once it’s trimmed, painted, and tiled.

It’s starting to make sense now, right?  I hope so!  🙂

And even though it’s sooooo far from complete, I went ahead and added the electric insert just because I was anxious to see how it would look.

It’s a perfect fit!

Today I’ll move on to the trim work, and hopefully the weather will cooperate so that I can get some painting done!