Set the posts for the platform for the fireplace. Pour concrete piers or supports at the corners of the platform and use anchor bolts to attach treated 4-by-4-inch posts. Cut these posts to the planned level of the base of the fireplace. If the base of the fireplace opening is planned to be 6 inches above the existing deck, cut the posts to a level that is 6 inches above the existing level.
Frame the platform with 2-by-4-inch lumber and cover with 5/8-inch plywood or flame-retardant materials if required by local codes. Using the 4-by-4-inch posts as corners, construct a floor frame of 2-by-4-inch lumber, spacing the boards so the centers are spaced 16 inches apart, within a frame of 2-by- 4-inch lumber built around the four corner posts. Also frame the front, back and sides below the floor of the platform if they are visible. Use treated 2-by-4-inch lumber, spaced 16 inches apart, for the framework below the floor of the platform for added durability.
Place the fireplace insert on the platform. Utilize a fireplace made of stainless steel for weather resistance. Attach the flue or chimney above the fireplace insert according to manufacturer's instructions.
Build a frame from 2-by-4-inch lumber around the insert and chimney. The design of this cover is up to the builder. Construct low walls around the fireplace using the 2-by-4-inch lumber spaced 16 inches on center between a top and bottom plate or board. Use 16 box nails in the stud framework. Connect the short walls at the corner. Use the same techniques to build stud walls or framework to cover the chimney portion of the project. The exact design of the framework is dictated by the shape and size of the fireplace insert, and the planned design elements of the exterior of the project. Cover the wood framework with exterior-grade plywood.
Cover the plywood exterior of the fireplace project with stone, stucco or brick. Install the exterior finish according to the manufacturer's instructions. You can use any cover that fits with the décor of the home. Add any trim or finish pieces necessary to complete the project.
Things You Will Need
- 4-by-4-inch treated lumber
- 6-inch anchor bolts
- 2-by-4-inch lumber
- 16 box nails
- Fireplace insert
- Flue or chimney
- Stone, brick or stucco exterior siding
- Allow enough room around the fireplace for chairs and other furniture necessary to enjoy an evening's fire. Place a fire-resistant material in front of the fireplace opening to create a hearth.