Let’s define exactly what’s a mantle and what’s a hearth. A mantle is the shelf above the top of the fireplace opening. Depending on the size of the fireplace and the way it’s finished, mantles are typically between four to seven feet long and five to 12 inches deep. They are made from brick, concrete, tile and wood, including old barn beams and split logs. Mantles can be combustible or non-combustible.
For safety, most zero-clearance (ZC) wood burning fireplaces will require between two and three feet of clearance above the fireplace opening to the mantle. Furthermore, there may be different requirements from the manufacturer for the same fireplace for a combustible vs. a non-combustible mantle.
There are also limits regarding the depth of the mantle. For example, a mantle that is 66” long x 12” deep will likely need to be installed further above the fireplace opening than a mantle 66” long and 6” deep. So always check the installation manual. The details regarding mantle placement and size are important.
THE WOOD BURNING FIREPLACE HEARTH
The hearth is that floor space directly in front of the fireplace. With a wood burning model, the hearth must be made out of a non-combustible material. This is done to protect the floor against heat and any errant sparks or embers that pop out from the fire. Brick, stone, slate and tile are commonly used. The hearth requirement will include dimensions that extend it beyond the width of the fireplace’s opening. The depth requirement can vary from 16” to 20”, depending on the model. Again, remember to check on the manufacturer’s minimum requirements. Here’s a typical requirement for a zero clearance fireplace. A diagram similar to this, is available for all ZC units.
There may be prerequisites for the way the hearth is constructed. By this, we mean those materials used beneath the brick or tile or slate. The heat from the fireplace may require the hearth to be built with some sort of non-combustible insulating material, such as a mineral fiber or ceramic board, and/or a specific thickness of cement board or air space.
WHAT ABOUT WOOD BURNING INSERTS?
Wood-burning inserts are a very popular appliance used to improve the efficiency of an older or open burning fireplace. The information above regarding mantles and hearths will apply to wood-burning fireplace inserts, too. Inserts are tested and listed by the manufacturer and their clearance requirements will be readily available.
If you are planning a wood insert project, do not assume that the mantle and hearth requirements for your existing wood burning fireplace are adequate to accommodate an insert. They may or may not be. Clearance requirements, dimensions for proper fit and other finishing details will be carefully evaluated by your WE LOVE FIRE expert.
Many people planning to install a wood burning fireplace insert, often replace the mantle and upgrade the hearth at the same time. Fireplace insert remodeling projects, are popular because they can update older, out-of-date family rooms while greatly increasing the amount of heat delivered to the home.
REGARDING GAS FIREPLACES AND INSERTS
Gas fireplaces have requirements that are substantially different than wood burning units. Some higher heat output models have strict requirements, while others may have no hearth requirement at all! Some gas fireplaces have non-combustible facing requirements while others allow wood trim to be in contact with the sides and top of the unit.
It’s not uncommon for a customer to come with a picture and ask their WE LOVE FIRE dealer to duplicate it. The fireplace, the mantle, the hearth, the stone and the lighting are appealing. Generally speaking, it’s very likely the look and feel of the picture can be matched with a gas model.
Clearances for the hearth and mantles with wood burning fireplaces are much more stringent than for a gas insert. Mantle and hearth requirements for gas fireplace inserts are seldom an issue.
PLANNING THE PROJECT IS THE KEY!
We’ve mentioned these many times before, but a couple items bare repeating. When it comes to clearance requirements for fireplaces, “more is better”. If a mantle requirement is 28” above the fireplace opening, install it 30’ or 32” above. If a hearth extension says 18” minimum, there’s not a thing wrong with going 20” – 24”.
Product brochures and/or the owner’s manual is where to find the specific details for the mantle and the hearth specifications for your fireplace. Your WE LOVE FIRE expert is very familiar with this information, too. Don’t be hesitant to ask.