Choose a fireplace. You can go with a simple fire pit and use charcoal or wood as your fuel, or you can install a gas outdoor unit. If you already have gas lines installed around your home, you can have a professional connect your gas unit to the existing gas lines. You can also look into a propane-powered unit, if you prefer to use gas but do not have gas lines available.
Design a frame, including the chimney. The frame should essentially be a large square or rectangle that encompasses the fireplace unit or fire pit. The exact dimensions will depend on the size of the unit you are building. Measure around your fireplace unit to determine how large the base of your frame needs to be. You want your base to enclose the fireplace without suffocating the fire.
Plan for the chimney to be high enough to expel smoke and ash far enough overhead that it won't be irritating when you're sitting around the fire; it should be at least 8 feet high.
Use 4x4 posts and 2x4 posts to create your planned frame; the 4x4s should be your vertical supports, and the 2x4s should be your horizontal supports. Cover the frame with 5/8-inch plywood.
Install the fireplace unit and get it hooked up to gas lines, if using a gas fireplace.
Cover the entire frame with 15-lb. felt paper, followed by a wire lath, which you will need to nail on. Once the lath is secure, apply a coat of mortar and let dry thoroughly.
Apply the stone. Spend some time figuring out how the stones will fit best onto your frame. You want them as close together as possible. Once you have a design in mind, apply mortar to the back of each stone and attach it to the frame. Repeat until the entire frame, all the way up the chimney, is covered with your stone. You may have to break some stones into smaller pieces in order to get a tight fit.
Apply a coat of mortar between the stones and let dry.
Things You Will Need
- Fireplace unit or fire pit 4x4 and 2x4 posts 5/8-inch plywood Stone Mortar 15-lb. felt paper Wire lath
- The simplest outdoor stone fireplace is a fireplace with a low stone wall around it. You eliminate the need for a frame and a chimney completely. Simply place your fire pit, or dig and install one yourself with concrete, then build a low stone wall around the perimeter.