
Looking to add some ambiance to your living room? The focal point that is both stylish and functional? Building your very own custom fireplace can give a room a major lift and create space where you can make memories. But it doesn’t have to take thousands of dollars and tons of time to get it done. New fireplace inserts are functional and stylish while also being very simple to install. They come in many sizes, finishes, with many lighting and flame effects that you are sure to find one that will fit your specific needs. This fireplace was gifted to me by TouchStone Fireplaces! Check them out for more stunning fireplace options. Our fireplace is linked below.
For this type of project, there are a couple of things to keep in mind when deciding before you move forward:
If you have access to power, there is room to mount your insert, and you’re good with the heat function, then let’s talk about what we did.
1.) Do you have a power source (outlet) close enough to power the fireplace insert?
2.) Will you be hanging anything above the fireplace (mantle, TV, art, etc.)? If so, will there be enough room?
3.) While inserts can provide heat, most will not heat a whole house. So if you are considering it as the main heat source, you will want to research the options out there.
Custom Fireplace Basic Design

For this project, we opted to build a small popout “wall” that would both allow for the fireplace insert to mount into but also to allow the TV to be hung as well. The depth or how much you want the wall to pop out is up to you as fireplace is very slim and only needs about 9-10″ of overall depth. Check the specifications on the unit you select as it may vary.
We decided to go with a 22″ pop-out primarily because there are going to be some shelves and console-style cabinets added later that is 19″ in depth so we wanted the fireplace and TV to be a bit in front of that. There will be another blog detailing all of that work when we get to it.
The basic structure consists of two “boxes” that will be the sides that then have crossbeams in the front and back to provide support and rigidity. That frame is then anchored to the existing wall with nails and lag bolts to ensure a completely safe frame to then hang drywall and eventually the fireplace and TV too.

Knowing the height and the depth it was now just about how wide to make it. This is up to you and will vary based on the size of the TV, mantle, and fireplace you have. For us, 60″ fireplace plus some space around the fireplace put the 80″. With all the dimensions figured, time to draw up plans. A couple of things to keep in mind. Drywall comes in 4′ X 8′ sheets, so there will need to be a crossbeam every 48″ to be able to attach them to. 48″ to the *middle* of the beam! So you have some wood to attach the drywall to.
Time to pick up some lumbers, drywall, screws, and nails.
Materials List:
(16) 2″x4″x10′
(3) 4’x8′ drywall
box of drwall screws – 1 1/4″
box of wood screws – 3″
(3) drywall square corner – 8′
(1) concrete color – gray
(4) drywall compound – 3.5 qts. (1 for drywall; 3 for “plaster”)
(2) 1 gang wall electrical box
Tools:
Mitre Saw
Cordless drill
Nailgun
Jigsaw
Pocket hole jig
Wood glue
Clamps
Drywall taping knife – (1) small (1) large -10″
Cordless drill paint mixer tool
level
tape measure
Optional access door:
(2) door hinges – 1.5″
(4) L brackets – 1″
magnets
Building the DIY Fireplace
Step 1: Build side walls / boxes
The sides are pretty straightforward. Cut lumber to the height you need, twice for each side for a total of four. Adjust for the width of these and cut your cross supports to get your total depth dimension. I spaced mine roughly every 21″. Because these boxes are narrow, I’m not worried about my drywall lining up. You’ll see what I mean later. Using the pocket hole jig, I drilled holes for the screws and attached the wood with a little glue to ensure a nice snug and permanent fit.
Step 2: Dado joints
For the cross beams, I used a dado-style joint. This provides a nice flush finish will provide an extremely strong joint between the pieces of wood. To make this joint, I used a jigsaw to cut out a “notch” the size of the crossbeam that will attach there. With this joint, I can add some wood glue and a screw and I will have an extremely strong joint.
I first figured out where along with the height of the sidewall that the fireplace would go – top and bottom to match the specifications of the fireplace. Then where the “mid 48” and “mid 96″ needed to be for the drywall, where the TV would mount (top and bottom), and then if there were any large gaps to add another cross. For the back, I cut two to match the front 48″ and 96”. These would be what I would lag bolt to the wall to anchor it.
Step 3: Vertical studs
The key vertical studs would be those for the outside dimensions of the fireplace, the TV, and then general support for the front of the wall. Normally studs are spaced every 16″, but I spaced it out a bit to 18″ to save on wood. The studs would be toenailed into the cross beams, so I didn’t drill pocket holes except for the tv and fireplace studs to make sure they were in the exact spot I wanted them.
Step 4: Build out the wall
I started with the sidewalls and got them into place. I needed some help to prop them up while I got the first crossbeams in place. After the first two were in place, the “wall” was stable enough to free stand and then I started to build out from there. I checked for the square to make sure everything was lining up, but as long as the math was right we should be good. Adding the remaining cross beams front and back, the popout was done. I think used a stud finder to locate studs on the existing wall, marked them, and then drilled and lag bolted to the wall. I think toenailed along the back side walls to the existing wall for some added anchor points.
Then I added all the vertical stud pieces and my entire popout frame was done and ready for drywall.
Step 5: Drywall

Knowing that my overall height is 9′, two 4’X8′ sheets on their sides would get me to 8′. This is why I needed the 48″ and 96″ beams to be able to attach the drywall to it. I cut the drywall using a utility knife and a long straight edge. You just need to score the rock side and then apply pressure from the backside of the score and the drywall will “break” along the score. Use the utility knife to scrape the roughness of the breakout and then attach the drywall with drywall screws. About every 10″. Make sure to sink the screw down below the surface just a bit. When you go to “plaster” over it, there won’t be a bump. In one of the sidewalls, cut a hole for the outlet box. You can do this before you attach the drywall to the frame. This should be near the bottom for the power to the fireplace to run through and your wires for your TV.
After the front is done, continue to score and break pieces as you need to fill the sides and the top of the front wall. Don’t go all the way to the top or bottom or sides. Joint compound will hide a lot, as well chaulking.
Before you close up the sidewall, go behind the front and cut out the hole for the fireplace. You should be able to follow along with the wood as it should be the size specified in the instructions and you should have already pre-measured all of this. Also, cut out and install your outlet box for the TV wires to pass through the front. Then close up that side wall with drywall.
Use the taping knives to apply the joint compound to cover all your seams and screw holes. Add a fair amount of compound to the corners then overlay the square corner to it. It should have holes that allow the compound to squish through as you press it into place. Add some more compound to smooth it out – a bit.
Let all this dry overnight. Clean your knives, you’ll need it tomorrow.
Step 6: Plaster

Add *a little* of the concrete color to a fresh bucket of the compound. I used about 1 oz. Maybe 1.5 oz. Using the paint mixer attachment and the drill, mix until the color is uniformly mixed in the joint compound. Now there is no wrong method. Apply joint compound to the drywall and “plaster” the front and sides. Swirls, scrapes, up, down, left, right. Texture the walls however you like. Don’t go too heavy but use as much as you’d like.

Let this dry overnight. Clean your tools!
Step 7: Mount fireplace and TV
Before you mount the fireplace, crawl through the opening and pull all your TV wires through the sidewall and up through the front outlet box. Once you close up the fireplace, you won’t be able to get back here unless you build an optional access door. Basically, you cut a “door” out of the side, add hinges, and use magnets and L brackets to create a stop for the door to open and “latch” to. If not, the fireplace can be removed pretty easily if you absolutely need to get back in there.

Videos of the Fireplace Being Built
The fireplace should “slide” into the opening with little fuss. Pass the power cord through the electrical outlet opening before you anchor it in place. Connect to power once everything else is done. Follow the fireplace instructions on how to set it up before installation. Once installed, arrange the rocks, logs, or other decorative pieces that may come with it.
Mount the TV using your wall mount hardware. This should line up with the studs you premeasured when you built the front.
Here is a video of step 2 of the fireplace build!
We added baseboard trim to the bottom. Crown molding for the top. Corner molding for the sides and caulking to tidy everything up.
Now the moment of truth. Turn on your fireplace and enjoy!!
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