You probably are aware the chimney is an essential part of a fireplace setup. But do you know how the chimney works? Do you know what the smoke shelf does? How about the Lintel? It's important to be an informed fireplace owner so you can properly care for your fireplace, and if anything goes wrong you'll know exactly what is going on and how you can get it fixed.

The firebox is what people usually mean when they say “fireplace.” It’s the main, rectangular part of the heat-producer, where the fire or gas log set is built. Fireboxes are usually surrounded by fireproof firebricks, but prefabricated fireboxes tend to be made of some sort of heat-resistant metal. The firebox can be painted specific colors or with different materials depending on the homeowner’s desired aesthetic.  

The hearth forms the base of the firebox and extends further out into the room in both directions. A lot more attention is given to the hearth, as it faces the room and gives the fireplace its character. Despite its aesthetic emphasis, the hearth has an important function: serving as a buffer between the fireplace gas valve or burning logs and the home by catching hot embers that can jump from the fireplaces directly into your home.

Because it has to contain fire, hearths are made of fireproof materials, such as granite, marble, brick, or stone. An optional fireplace screen is sometimes added to the hearth as an extra layer of protection to the room. The depth and materials used for the hearth are subject to local building codes.

This one is more straightforward. A fireplace face is the panel that wraps around the opening of the fireplace, separating the hot firebox from the combustible elements of the living space. A fireplace face is similar to a hearth in that it is a non-combustible buffer that wraps around the firebox.

The “surround” is a term applied to the entire assembly of fireplace pieces: mantel, legs, hearth, etc. At the end of the day, the surround is what makes up all visible parts of the fireplace (except for the firebox).

A fireplace’s back panel improves the fireplace’s overall design by complimenting the hearth. The back panel is located between the opening of the fireplace and the surround.

The mantel is a shelf on above the fireplace’s opening on which valuable items can be place, traditionally trophies, photos, or family urns. Although the mantel is used a shelf, it is useful for keeping smoke from entering the room.

If you plan on mounting a television above your superior fireplace, a mantel can do a great job obstructing heat from the fireplace, thereby protecting your electronics while creating a visual separation between your fireplace and TV. 

Located at the top of the firebox, the lintel is a structural element that helps spread the stress of the chimney across the sides of the fireplace.

The throat of the chimney is located at the base of the chimney and the top of the firebox. It is the in-between area where fireplace directly meets the chimney and is therefore non-combustible.

The damper is usually located within the chimney throat, but sometimes can be found at the top. A damper is a fire-resistant plate that covers the entire internal area of the chimney. A throat damper is operated manually by a handle or lever, and it should be opened every time the fireplace gas valve or log fire is in use, as it opens ventilation from the firebox to the chimney.

When the fireplace is not in use, however, the damper can be closed to prevent warm air from being lost to the outside. The damper can also be closed in order to reduce the draft coming through the firebox from the outside, through the chimney.

Homeowners should ensure that the fireplace damper is open before building a fire.

Technically, the chimney is the area through which the smoke and gas byproducts exit the home. A chimney is the “direct vent.” The chimney begins at the top of the firebox (where combustion byproducts begin) and continues towards the roof.

Chimneys should be maintained regularly to avoid any sort of creosote buildup or structural weaknesses that could spread to the rest of the home.

The chimney cap is a manipulative piece located at the top of the chimney. A chimney cap is a small, but crucial element to this chimney: it prevents wet weather, animals, and debris from making their way into your home through the chimney.

Not all chimneys have a chimney cap, but they can be installed to prevent any moisture-related damage to your chimney, flue, or firebox.

The crown, located next to the chimney cap, serves a similar purpose: to protect the elements within the chimney from the weather. Specifically, the crown works to keep moisture from entering the chimney, drastically expanding the structure’s lifespan

The flue is the passageway of the chimney, extending from the firebox to the chimney cap. The flue is specially lined with a heat-resistant material to protect the structure of the chimney from outside moisture, as well as the intense heat, smoke, and chemicals produced by the fire’s combustion.

The flue lining is crucial to the fireplace, as it keeps the fire separate from the combustible parts of the attached home.

Located above the chimney throat or damper, the smoke chamber structure is built to compress the fire’s smoke and chemical byproducts as it floats up the chimney, towards the roof.

The smoke shelf helps prevent backdrafts from coming down into the firebox. Much like the damper, the smoke shelf is another piece included in the chimney to keep moisture, smoke, and debris from reentering the home through the firebox.

Glass doors are found, traditionally, on fireplaces as a decorative piece to add some tasteful separation between the living space and the burning firebox. Sometimes, instead of glass, doors are made of a metal screen.

Glass doors also work well to keep hot embers, ash or any smoke from entering the living space, which can happen if the home happens to be airtight. However, the US Fire Administration recommends that glass doors should remain open while having a fire.

An optional piece to the chimney, the ash pit, may be located underneath a fireplace. The purpose of the ash pit is to catch and store ash that falls from a log-burning fire. If your superior fireplace is not equipped with an ash pit, you will have to manually gather and clean the accumulated ash after fireplace use.

For all its many preventative engineering components, chimneys aren’t perfect! There are still complications that can crop up over a chimney’s long lifespan, especially if it’s been a while since installation and maintenance.

If a chimney isn’t built with enough height, for example, an ambient updraft can prevent smoke from exiting through the chimney as it should. Similarly, negative air pressure caused by an excessively airtight home can pull smoke from the fireplace into the home and away from the chimney.

It’s important to understand how exactly a chimney handles smoke, as any malfunctioning can cause toxic fumes to enter the home. As a precaution, ensure that your carbon monoxide detectors are functional—and if you don’t have some already, buy them ASAP, no matter the situation. Every home should be equipped with a carbon monoxide detector.

If you have a wood-burning fireplace, be on the lookout for creosote buildup.

Every time wood is burned in your firebox, combustion is produced, and smoke rises to exit through the chimney. As a byproduct of this process, however, creosote, a fine carbon powder, is deposited into the chimney. This creosote can build up in the flue lining and is flammable.

To prevent a chimney fire, have your chimney be inspected and cleaned annually by a professional. This way, you can avoid the danger involved in any creosote buildup.

Beyond the dangers associated with building fires, the structure of the chimney itself can cause problems for a homeowner. Because a chimney sticks outside, it is quite susceptible to the elements: wind, precipitation—anything flying over, even. Over time, it’s possible that the outside moisture could damage the chimney’s brickwork, the masonry of the firebox, the lining of the flue, or the damper.

For this reason, you should have annual cleanings and periodic inspections of your chimney. Additionally, you can purchase a chimney cap, which will protect the chimney from moisture, as well as other potential invaders like outdoor debris, rodents, or the occasional bird's nest.  

Even with the damper, flue, and chimney cap, it’s possible that your chimney backdraft could cause unpleasant odors to enter the home through your fireplace. The cause for this could be water entering the flue and mixing with the creosote leftover from wood-burning fires.

To prevent campfire-esque smells from spreading into your home, try to make a habit out of shutting the damper after putting out your fire. Don’t open the damper right after extinguishing your fire, however: wait until the ashes in the firebox have gone cold, and everything is safe to touch.

You can also check to see if your chimney has a cap; and if not, you can get one to prevent any precipitation outdoors from getting inside your chimney. Remember, it’s the moisture causing the odor—not necessarily the fire. If this doesn’t work, try getting new firewood. It’s possible that the current firewood’s quality isn’t up to snuff.

Once you’ve taken all the above steps to get rid of that smell, call a professional. It’s possible you just need to clean the creosote out of your chimney; or maybe there’s a dead animal in your flue.

If you don’t have a chimney cap, there is the potential for moisture to mix with creosote deposits, which causes the lining to crack or deteriorate. If there is any damage to the lining, it needs to be replaced immediately.

The lining is what seals off the combustible part of the home, acting as a buffer between the fireproof flue and the normal, flammable parts of the house. Therefore, if the lining is damaged, there is the risk that any log fire thought to be contained in the firebox can spread outside the chimney. If you have any reason to believe the flue liner tiles of your installation may be damaged, contact a licensed professional to inspect the chimney. 

Although there is a lot of research and maintenance required for chimney-owners, it’s all worth it when you’re able to start a nice, log-built fire in the privacy of your living room. As with most home improvement projects, it’s all trouble until installation—then comes the payoff: years of convenience and impressing your guests!

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If you have any doubts about getting to achieve your fire pit dreams, feel free to call us at 866-848-3473 or send us an email. Our NFI-certified experts are here to answer any questions or schedule an inspection for your existing fireplace or your covered patio to let you know if it is suitable for a fire pit. Browse our section or check out our other Learning Center articles to expand your fireplace knowledge.

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