An outdoor fireplace has three main structural components:

1. Base - A reinforced concrete slab is the best base for an outdoor fireplace. An outdoor fireplace base should be designed and built according to your soil type, freeze/thaw conditions and the weight of the fireplace. Areas with wet soil or frequent freeze/thaw cycles will require a thick concrete slab with lots of rebar or wire mesh reinforcement and footings that penetrate below the frost line. Custom built outdoor fireplaces tend to be heavier than prefab ones, which means that they will require a thicker and stronger slab. If you are having a new concrete base slab poured it should be 6 inches larger than the fireplace on the rear and sides, and at least 24 inches larger in the front. If you want to have a fireplace built or installed on an existing patio, have the integrity of the surface assessed by a professional beforehand. Talk with a landscape designer, experienced masonry contractor, or your prefab fireplace manufacturer to find out the exact specifications for the base and footings for your outdoor fireplace project.

2. Firebox - The firebox is the portion of the fireplace which will house the actual fire. You may purchase a stainless steel firebox designed for use outdoors or opt for a custom built firebox. Firebox sizes range from 30" to 50" across. For safety reasons, fireboxes should be lined with fire brick. If ordering a firebox you will most likely have a few firebrick patterns and colors to choose from. You will need to know if you plan to fuel your fireplace with wood or gas prior to ordering or building a firebox because the requirements are different. (Outdoor firebox manufacturers: FMI, Napoleon, Monessen)

3. Chimney or Vents - A wood burning fireplace requires a smoke chamber that leads to a chimney with a spark arrester; a gas fired fireplace only needs exhaust vents. Therefore, if you do not have the space for a tall structure, a gas fired fireplace is the best option. A chimney must be two feet higher than any structure, including patio covers, sheds and your home, that is within 10 feet of the chimney. Since outdoor gas fireplaces do not produce smoke and ashes, a chimney is not required. Vent free gas fireplaces are a common option outdoors.

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