How To Build a Fireplace on an Outdoor Patio

Learn how to create an inviting outdoor space with a fireplace.

Highlights:

Step 1: Prepare the Fireplace Insert
Step 2: Attach the Tar Paper and Lath to the Frame
Step 3: Add the Mortar
Step 4: Begin Adding the Stonework
Step 5: Fill in the Gaps

Step 1: Prepare the Fireplace Insert

Measure your fireplace insert and construct a frame per the measurements. Be sure to check for level at each pass (Image 1). We used 2x4 lumber and OSB plywood to create our fireplace frame. After constructing a frame, attach any hoses or accessories to the fireplace (Image 2) and place it inside the new frame (Image 3). Drill screws into the frame to keep it in place.

- Image 1
- Image 2
- Image 3

attach hoses or accessories to fireplace

Lucie Rowe

Step 2: Attach the Tar Paper and Lath to the Frame

Next, cover your frame with 30-lb. tar paper (Image 1). This will act as a moisture barrier for your fireplace. Attach the metal lath over the tar paper and onto the frame using a nail gun (Image 2). The metal lath will provide support for the stone that will be placed on top. Install the lath rough side up so that the mortar scratch-coat will adhere properly.

- Image 1
- Image 2

cover frame with tar paper to reduce moisture

attach metal lath over tar paper with nail gun

Lucie Rowe

Step 3: Add the Mortar

Mix your mortar according to the manufacturer's directions. Apply a generous amount of mortar to the metal lath using a trowel, pushing it upward onto the lath. Be sure to keep the top of the trowel angled, and the bottom flush with the surface until the lath has an even scratch coat. Let the mortar dry overnight.

apply even scratch coat over surface of mesh lath

Courtesy of Lucie Rowe

Step 4: Begin Adding the Stonework

Mix the mortar for your stones and spread a half an inch thick layer to the back of each stone. Place your stones beginning with corners (Image 1) and work inward. When placing the stones (Image 2), hold each firmly in place for 20 to 30 seconds before releasing. To prevent continuous joints and provide a more natural look, alternate placement of stones with different sizes and colors.