How to Build a Fireplace
A crackling fire in a brick or masonry fireplace adds undeniable charm to any home. Yet fewer houses than ever have wood-burning fireplaces with chimneys. Gas-burning fireplaces are an option, but many types must be vented and gas plumbing is required.
A safer, easier, and more environmentally responsible way to build a fireplace that doesn't require venting is with an electric fireplace insert built into a false fireplace wall. It's a style that's gaining in popularity since the fireplace wall can be faced with veneer brick or masonry, to look just like the real thing, or even with combustible materials.
Building a Fireplace With an Electric Fireplace Insert
Electric fireplace technology has progressed beyond blower-driven plastic faux flame strips and now looks more realistic than ever. Today's electric fireplace inserts create the illusion of random flames behind protective glass. Behind the glass, lights shine against a rotating spindle embedded with reflective materials.
In some cases filtered through flame-shaped stencils, the reflections dance on the glass and move upward, just like real flames. Faux logs, crystals, rocks, or broken chunks of glass line the base of the insert.
Electric fireplaces can be wall-mounted, just like a flat-screen TV. The fireplace insert in this project is recessed for added firebox depth and greater realism. The insert slides into a fireplace wall built from two-by-six lumber.
Fire is not a concern because the insert contains no flames. So you can use any facing material: shiplap, painted wood, or in this case, veneer brick or stone.
Some fireplace inserts have heaters to complete the illusion and heat the room. Most fireplace inserts run from standard 120V electric outlets.
Vent the fireplace insert according to the manufacturer's instructions for inserts with added heaters and blowers. Some units pull between 750 and 1,500 watts, so the outlet may need to be dedicated to the fireplace only in order to avoid circuit breaker nuisance tripping and for safety.
What You'll Need
Equipment / Tools
- Electric miter saw
- Tape measure
- Hand saw
- Speed Square
- 5-gallon bucket
- Stud finder
- Wet tile saw
- Electric fireplace insert
- 10 two-by-sixes
- 5 cement boards, 1/2-inch thickness
- Manufactured veneer stone, 92 square feet
- Cement board tape
- Veneer stone mortar
- Cement board screws, 1-1/4-inch
- Screws, 3-inch
Locate the Fireplace
Locate the fireplace above or near a grounded 120V outlet. Avoid areas of direct sunlight as the faux flame will wash out in bright light. If the fireplace insert has a heater, consider whether or not you want to locate the fireplace under a TV.
Remove the Baseboard
With a prybar, remove the baseboard from the wall.
Size the Fireplace Insert Mounting Frame
You'll use two-by-sixes a build a frame to hold the fireplace insert within the fireplace wall. The frame's inside dimensions should match the size of the fireplace insert's rough opening dimensions, with 1/8-inch extra on all sides. The fireplace insert's instructions should list rough opening dimensions.
The mounting frame will be made of two-by-sixes, one at the top and one at the bottom and two on the sides. The length of each horizontal piece should equal the width of the insert, plus 3-1/4 inches. The two vertical two-by-sixes (left and light) should be the stated rough dimension height plus 1/4-inch.
For example, if the instructions' stated rough dimensions are 18 inches high by 36 inches wide. Cut two boards to 39-1/4 inches each and two boards to 18-1/4 inches each.
Build the Fireplace Insert Mounting Frame
With the drill and using 3-inch screws, build the fireplace insert mounting frame. Be precise when attaching the boards to keep the frame square. Test the size by slipping the fireplace insert into the frame.
Calculate the Fireplace Wall Height
Because the fireplace wall will be built on the ground and then tilted up, height is a concern. Tilt-up walls cannot be as tall as the room's ceiling height. Reduce the height by 2 inches to allow for the height of the wall as it's being tilted up.
As an example, the ceiling is 90 inches high. Subtract 3 inches to allow for the top and bottom horizontal two-by-sixes. Subtract another 2 inches so that the wall can be tilted up. So, the vertical two-by-sixes should be cut to 85 inches long.
Build the Fireplace Wall
Construct the fireplace wall from seven vertical two-by-sizes placed between two 8-foot-long horizontal two-by-sixes, much like an ordinary wall system. Space the studs every 16 inches, on-center. Use two screws per attachment point.
Attach the Mounting Frame to the Fireplace Wall
Lay the mounting frame on top of the fireplace wall and center it. Choose a height that is visually appealing but also one that is close enough to the outlet for the fireplace insert to plug in.
Mark the vertical studs that will need to be cut. Remove the mounting frame. Continue the mark downward with the Speed Square. Cut on the lines with a hand saw. Insert the mounting frame. Attach the mounting frame to the studs by screwing through the inside of the mounting frame.
Block the Studs
Cut four two-by-sixes, each piece at 14-1/2 inches long. Add these four pieces between the studs, flat and flush with the back of the wall, to help attach the fireplace wall to the house's wall. Have two blocks below the fireplace insert mounting frame and another two blocks above it. Screw the blocks into place through the studs.
Attach the Fireplace Wall to the Room Wall
With an assistant, tilt the fireplace wall up so it is vertical. Move it into place against the wall. Make sure that the outlet will be between two of the studs and will not be covered up by any of the studs. With the stud finder, locate wall studs (of the house) behind the stud blocks installed earlier. Use 3-inch screws to attach the fireplace wall.
Add the Cement Board to the Fireplace Wall
Screw the cement board onto the studs of the hollow wall. Be sure to sink the heads of the screws. All vertical edges should land on a stud. Tape all seams with cement board tape. Mix up a small amount of mortar. Using the trowel, cover the tape with mortar.
Cement board can be added directly to studs with no sheathing or support as long as the studs are 16 inches on-center and 1/2-inch cement board is used.
Install the Fireplace Insert in the Fireplace Wall
Plug in the fireplace insert. Slide it into the mounting frame. Before attaching the insert to the frame, hold a sample piece of veneer on the cement board next to the fireplace insert. The fireplace insert should match the edge of the stone veneer, plus another 1/4-inch to account for mortar. Attach the fireplace insert per the manufacturer's instructions.
Attach the Brick or Stone to the Fireplace Wall
Cut a 1-inch strip of cardboard and band the perimeter of the fireplace insert with it to protect the insert.
Create a dry layout of the stone veneer on the floor next to the fireplace wall.
Cut as much of the stone veneer as possible beforehand. Use a wet tile saw to cut the veneer.
Mix the stone veneer mortar with water in the 5-gallon bucket.
Apply mortar to the cement board, plus butter the back of each stone before applying it to the wall.
Maintain a 1/8-inch gap along the floor and walls.
At the top, extend the top row of veneer stones 1/4- to 1/2-inch above the top edge of the fireplace wall to cover the edge.
Upon completion, remove the protective strip from the fireplace.
When to Call a Professional
Some fireplace inserts may need to be hard-wired into the home's electrical system rather than using a cord that plugs into an outlet. If this is the case, hire a qualified, licensed electrician to wire the fireplace directly into an electrical box in accordance with local codes.
Energy Efficiency and Your Wood-Burning Appliance. Environmental Protection Agency (EPA)