Step 1: Build the Support Frame

Measure the height of the ceiling. Subtract 3" from the overall height and mark this length on two 2x4s for wall studs. Cut the studs to length.

For the top and bottom plates, cut two 2x4s to length. These pieces should be 6" wider than the fireplace.

Nail the frame together with the stud ends butting against the sides of the plates.

Step 2: Attach the Frame

Maneuver the frame into place and check for vertical level using a 4' level. Make adjustments by striking the frame with a hammer (Image 1).

Use 10d framing nails or deck screws to attach the frame to the ceiling joists (Image 2).

If you are installing the frame on a tile floor, use a masonry bit to pre-drill holes through the grout lines, then use deck screws to attach the frame to the floor.

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    Image 1

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    Image 2

Step 3: Create the Rough Opening

Determine where the bottom of the fireplace will rest and mark the rough opening at top and bottom (add 1-3/4" to this measurement to allow for a plywood shelf thickness and provide clearance and between the top and middle frame members).

Measure the width between the vertical studs and cut a three 2x4s to length.

Hold one of the 2x4s in place between the studs, flush with the front of the frame, and nail one end to the stud.

Check for level, and then nail the opposite end to the other frame stud.

Nail the second 2x4 to the existing wall studs, level with the middle section nailed to the frame.

Insert the third 2x4 between the frame studs, flush with the front of the frame, so that its bottom is even with the top rough opening marks. Nail this section in place.

Measure and cut a 3/4" piece of plywood that fits like a shelf across the top of the two middle 2x4 pieces. Use 8d nails or screws to secure this plywood in place.

Step 4: Install Vertical Supports

For the side rails that the fireplace will attach to, measure from the upper cross-frame piece to the plywood. Cut two 2x4s to length.

Mark and measure the rough opening width for the fireplace, centering this opening between the frame studs (add 1/2" to this dimension for clearance).

Attach the vertical rails to the marks, parallel to the studs.

Set the fireplace into the opening and attach it to the vertical rails with screws.