Fireplace Surround Requirements

Fireplace Footing

• The fireplace footing is the part of the foundation that is built up to support the fireplace hearth or insert. The fireplace surround should always be built on this footing. Trying to build a surround on other flooring materials could result in structural weakness and fire hazards. Always stay with a mortar backing. If you are planning to extend your surround, use a safe material such as cement fiberboard for a subfloor.

Hearth Extension

• The hearth extension is the front part of the surrounding, the bottom edge of the fireplace which extends out across the floor. For most fireplaces, this extension must be at least 16 inches deep and 8 inches wider on each side to protect the immediate floor from heat damage or combustion. Naturally, the surround materials should also be fireproof, which is why stone, brick and rock materials are all common. For very large fireplaces, with openings larger than 6 square feet, the extension needs to be at least 20 inches deep and a foot wider on each side.

Other Sides

• The fireplace surround doesn't just extend over the floor, it also borders the other parts of the fireplace opening, too. On the top and sides, the surround should extend at least a foot for proper fireplace safety. Headers can be used to support hearth extensions, but only if they are located more than 12 inches from the face of the fireplace.

Variables

• A number of variables can affect these general surround requirements. For example, if the fireplace is built up from the floor, the surround also needs to cover the space between the bottom of the fireplace face and the floor itself. Local building codes may add other requirements or extra length onto the surround, so always check your local codes before beginning the project.