Parts of a Fireplace & Chimney Explained (with Diagram)
Fireplaces come in different designs, shapes, sizes, and types. They are made up of numerous components both seen and unseen. Whether your model is operated by gas, by burning wood, or just for looks, it is helpful to understand the basic parts of a fireplace.
No matter how complex the parts may seem, most fireplace models share similar pieces and additional accessory options. For your unit to perform as expected, all of these pieces must be in proper working order. Developing an understanding of all the various components can help you diagnose potential problems and stay safe when you build a fire. You will also be better equipped to communicate with a fireplace specialist and discuss any problems with your unit.
While many believe that the fireplace and chimney are one and the same, they are actually separate pieces that work together to bring warmth to your home. The fireplace is made up of many parts including the hearth, firebox, mantel, and face. This is where you build your fire. Then, the chimney is the vent that safely exhausts heat from your home.
Read on to learn more about the different parts that make up the fireplace and chimney. We’ve also included some helpful photos and diagrams for a clear picture of what goes where.
Types of Fireplaces
Before we proceed with learning the anatomy of a fireplace and chimney, it’s important to note that there are different types. The two major designs are masonry and factory-built (or prefabricated) fireplaces.
Prefab units are ready-made and have very different parts than the more conventional masonry style. Both masonry and factory-built fireplaces can be either gas or wood-burning, depending on your preference.
How a Traditional Fireplace Works
When you light a fire inside your house, you are presented with two obvious challenges:
- How do you avoid your house catching fire?
- How can you prevent smoke from escaping into the room?
Fortunately, a fireplace solves both of these potential issues. Fireplaces are traditionally made of stone, brick, metal, tile, or a combination. These are materials that are fire-proof and will direct smoke out the chimney.
The most important mechanical purpose of a fireplace is to produce a draft. Your fireplace creates a column of heated gas inside of the chimney. As the air rises, more heated air is pulled from the fire after it. This process results in a draft, or a balanced flow of hot gases and smoke, up and out of the fireplace’s chimney.
As far as heating goes, a traditional fireplace uses radiation to produce heat. This is when warm electromagnetic waves carry heat to cooler objects, warm them, and cause their molecules to speed up. In this case, the heat from the fireplace send out waves that hit people and objects in a particular room. This speeds up their molecules, causing them to warm.
The Parts of a Fireplace
Let’s explore the different parts of a fireplace and chimney to understand how they work together to give you heat and a cozy glow when it’s cold out.
When you first observe a fireplace, your eye is often typically drawn to the firebox where the physical flames exist. However, this component works directly with another important piece known as the hearth. Unless you have a zero-clearance fireplace, both gas fireplaces and traditional wood-burning fireplaces are generally outfitted with a protective hearth.
In masonry fireplaces, you’ll generally have a hearth that is constructed out of bricks extending from the fireplace. In this installation, the hearth can be either flat or raised. While raised hearths rest on a platform that is a couple of inches off the ground, flat hearths sit flush with the floor. A flat hearth offers much more space for additional furniture and is cheaper to construct than their raised counterparts.
On the other hand, for prefabricated models, the hearth is typically metal and includes a decorative cover. The cover may be a porcelain-coated liner, cement liner with a brick pattern, or any other type of decorative material.
Often referred to as a fireplace front or overlay, the surround is the outer component of the fireplace that “surrounds” the fireplace and visually ties it into the room – hence the name. They cover any gaps between the fireplace and the wall giving your fireplace a tidy appearance. Fireplace surrounds are mainly decorative accessories and are not always made out of fireproof material.
Both prefabricated fireplaces and traditional masonry fireplaces have a number of decorative options to help the surround fit with the rest of the décor in the room. Prefabricated models are outfitted with a metal weldment, or front, that may be covered up directly with metal, stone, or brick.
When finished with brick, the fireplace’s facing can make it especially difficult to determine the difference between a prefabricated and masonry model.
The fireplace face is the outer front of your fireplace. It is made out of fireproof material and sticks out a few inches into the room. It is similar to a surround, however, the purpose of a fireplace face is both functional and decorative. A fireplace surround usually serves a purely aesthetic purpose.
The back panel sits between your fireplace and the surround. This is generally just for looks, although some can also serve a functional purpose. The back panel is usually made out of cast iron, granite, or slate.
Atop the surround, or on the top of the face of an open fireplace, is where the mantel sits. It offers a shelf for decorative items can be placed and Christmas stockings can be hung. In some cases, the mantel helps to prevent the smoke from the fire from entering the surrounding area.
The mantel design can be a relatively simple shelf or feature elaborate designs that extend all the way to the ceiling. Mantels also come in a variety of materials such as wood, stone, concrete, and more. Whether you prefer a modern, classic, Colonial, or Victorian style mantel, chances are you’ll find one that matches your design preferences.
Moving to the inside of the fireplace, the firebox is the term used to describe the enclosed component where the fire is built and actually burns. This designation is used regardless of the type of fireplace you have. The firebox is usually square or rectangular in shape.
As far as gas fireplaces go, the firebox is just a combustion chamber where the fire ignites. It consists of a floor, sides, and the top is lined with ceramic or firebrick liner for enclosing the flames.
To put things into perspective, the hearth is at the base of the firebox and the front of the firebox is often called the opening where you’ll usually find fireplace doors. Whereas, at the top of the firebox you have the damper, smoke shelf, and smoke chamber.
The lintel serves a mainly structural purpose, although it can be decorative as well. It helps to bear the weight of the chimney above the firebox. Its place is between the throat and the surround. This piece is usually made out of steel, concrete, or even timber.
Both gas and prefabricated wood-burning fireplaces have liners. Gas and ethanol fireplaces use either porcelain-coated reflective liners or ceramic liners. They not only protect the firebox from flames, but they also help to radiate heat back into your home. Also, they make the fire look lovely!
While masonry models tend to rely on firebrick to protect the fireplace, prefab fireplaces rely on an inner wrapper. This wrapper is typically hidden behind liners and is either a heavy gauge sheet metal or plate steel assembly/ This piece links the firebox together, giving it strength and shape.
Many fireplaces won’t have an ash pit. However, if you do have an ash pit, it can your fire-building life a bit easier. The ash pit usually has fire-resistant metal doors that are under your fireplace grate. When the fire is done, opening the doors will drop the ashes into a pit below. Many ash pits will hold a season’s worth of ashes. This means you don’t have to spend time and energy cleaning out your ashes each time you want to build a new fire.
Many fireplaces have glass doors on the front of the fireplace. While these look mostly decorative, they help keep the cold out when your fireplace is not in use. However, when the fireplace is in use, should these doors stay open or closed? The US Fire Administration (USFA) resolves this question for us. They recommend you always leave the glass doors open when you have a fire going. If you are worried about sparks flying out, many fireplaces have a chain curtain you can pull across the opening. Or, you can also add a freestanding fireplace guard in front of your fire.
Parts of a Chimney
Many people tend to think that the fireplace and chimney are one and the same, however, they are actually individual components. There are a number of parts of a chimney that are critical to the performance and safety of both the fireplace and the chimney itself. Here are some of the basic parts that make up a chimney:
A chimney’s outer material, such as bricks, is its’ foundation. If the bricks aren’t in good condition, you put the chimney’s structural integrity at risk and your own safety. Not to mention, the fireplace will not be able to function properly. Additionally, if you have damage to your bricks, moisture can penetrate your home and lead to mold and mildew concerns.
Put simply, the flue is a passageway for moving the exhaust gases from the fireplace to the outdoors. The flue protects the chimney from the heat of the smoke that is exiting. It also prevents any moisture in the outside air from entering your home. Most flues are made out of fireproof materials.
The liner is the fireproof material that keeps the fire confined to the chimney. It also prevents the smoke, from entering your living areas. The most common type of liner is fireclay tiles. This material is economical and long-lasting.
If even the smallest crack develops in a liner, you’ll need to replace or repair it immediately. Your fireplace will be unsafe to use until you fix the liner.
The chimney cap keeps out sleet, rain, snow, debris, and downdraft. The chimney cap can protect water from entering your chimney which will extend its life and add an extra layer of safety. It will even keep birds and animals out of your home! The wire mesh material serves as a spark guard protecting your roof from fires.
Also referred to as a chimney wash, the chimney crown is a piece of concrete that shields the top of a masonry chimney. While the chimney cap covers the flue opening, the crown covers the entire top of the chimney. It is usually a concrete material and prevents water from getting inside the chimney.
Chimney Chase Cover
Chase covers, or “top pans” are similar to chimney caps, however, as you can see there are a few differences. While a chimney cap covers a masonry chimney, a chase cover is used for the top of prefabricated chimneys. The chase cover shields the chimney opening and comes in a variety of materials such as aluminum, copper, stainless steel, and galvanized steel. Ideally, the cover will deflect rain and snow so moisture doesn’t enter your prefabricated chimney.
Due to their durability, copper and stainless steel tend to be the most popular options. Although, aluminum is also common since these come in more colors and are generally cheaper.
Made from aluminum, steel, copper, or vinyl, the flashing connects your chimney to your roof. It is a waterproof seal that will protect your roof, chimney, and the inside of your home from leaks and moisture.
Although these are some of the main components of a chimney, there are some others that are technically a part of both the chimney and the fireplace.
Shared Parts of a Chimney and Fireplace
The Smoke Chamber
Located between the damper and flue, the smoke chamber is a pyramid-shaped passageway. This area provides a smooth transition between the firebox and the beginning of the chimney. It compresses combustion materials, allowing them to safely exit out of the chimney instead of making their way back into your home.
Dampers, sometimes called throat dampers, are in the “throat” of the chimney, just above the firebox. It is a valve or door that controls the draft in an open fireplace.
When not in use, the damper helps to seal off the fireplace so that drafts don’t enter through the chimney. However, while you’re using the fireplace, you want to make sure that the damper is open. This allows the smoke to exit out the flue.
Maintaining the damper is crucial to the safe operation of your fireplace. If your damper is broken, smoke cannot escape out of your home. Or, if the damper becomes stuck in the closed or open position, you may get drafts.
While a smoke shelf is one of the unseen parts of your fireplace and chimney system, it plays a vital role. The smoke shelf is one more layer that protects debris and water from entering your firebox. It also blocks any drafts coming down your chimney. This shelf helps to make your home a warmer, safer place.
Gas Fireplace Venting
If you were to take a peek up into your firebox, you’d see the venting system. These systems are not a one-size-fits-all assembly. The type of heating your fireplace has will determine the venting system you require. With that said, here are some of the most common types of gas venting systems.
Direct Vent Fireplaces
Unlike conventional gas fireplaces, direct vent models do not use combustion air from the home to function. Instead, they operate based on a coaxial venting system with an outer and inner collar. There’s a small inner pipe for carrying exhaust gases outside. Then a larger outer pipe draws in combustion air to service the unit.
B-Vent Gas Fireplaces
B-vent gas fireplaces exist between vent-free and direct vents. They vent similar to a direct vent model but open to the living space like a vent-free fireplace. They have a realistic flame appearance and are relatively easy to operate. Like a wood-burning fireplace, b-vent gas units vent vertically.
Vent-Free Gas Fireplaces
Vent-free gas fireplaces are exactly as they sound and do not use a venting system. They release more heat than a wood-burning high-efficiency unit by limiting the BTU output. Since vent-free fireplaces rely on room air for combustion, they open up to the room.
Fireplace Blowers and Fans
Nearly every type of fireplace uses a blower to circulate heated air from the fireplace itself throughout your home. While a lot of heat from the fireplace could escape out of the vent system, blowers and fans prevent this.
Although masonry fireplaces rarely have blowers, some still use fans. Older models usually used ductwork embedded into the stone or brick with outputs in the ceiling and intake ducts near the floor. Whereas, direct vent gas, prefab wood burning, electric, and vent-free gas fireplaces will typically use a rotary style blower.
Fireplace Ignition Systems
With a better understanding of the parts in and around a fireplace, it’s time to explore what actually produces the fire – the ignition system. Fireplace ignitions systems have three different types, the match lit system, standing pilot ignition system, and the electronic ignition system. Let’s have a closer look at each type.
Match Lit Ignition System
The most traditional way to ignite a fireplace is by lighting the flames manually with a matchstick or long lighter. A match lit ignition system requires holding one of the aforementioned near the burner prior to opening the gas valve.
The valve controls the amount of gas you use, which changes the height of the fire. With this system, there are little to no moving parts so it is very low-maintenance. A match lit system is only available for indoor natural gas fireplaces. It does not have a standing pilot, and you won’t be able to use a remote control with this system.
Standing Pilot Ignition System
A standing pilot, or safety pilot, is another way to manually ignite a fireplace. However, it is slightly more advanced than a match-lit ignition system. Instead of using a long lighter or match, you can ignite the flame by simply turning the control knob inside the fireplace.
A small flame is constantly lit, even when you are not using your fireplace. If the pilot light ever goes out, the flow of gas automatically shuts off to avoid gas leaks. Unlike match-lit ignition systems, a standing pilot works with both natural gas and propane.
Electronic Ignition System
The final type of ignition system is an electronic, or non-standing pilot, system. This option eliminates the hassle of manually lighting your fireplace with a match, lighter, or control knob. It is incredibly convenient and requires a battery-operated connection or power-line connection to function.
A battery-operated connection is usually cheaper than wiring your fireplace to an electrical system, at least up front. However, with a battery-operated system, you will need to keep replacing the batteries.
The electronic ignition system is much safer and is also easy to use. It has a flame-sensing pilot feature that activates whenever the fireplace is not in use. This means that if your system detects the absence of flame, it will shut off the gas flow or try to re-ignite the flames.
Common Issues with Your Fireplace
While most of us won’t use a fireplace as a main source of heat, the extra warmth and flickering glow are delightful on a cold winter’s day. However, issues with your fireplace can be costly and can render your fireplace unusable. Some of the most common problems with your fireplace are due to:
- Smoke buildup (creosote)
- Birds and animals
- Tree debris
- Improper use of the damper
- Poor-quality firewood
- Lack of regular maintenance and cleaning
Now that you know more about the parts of your chimney and fireplace, it will be easier to explain any issues that you are experiencing to a chimney sweep or fireplace specialist.
Jessica considers herself a home improvement and design enthusiast. She grew up surrounded by constant home improvement projects and owes most of what she knows to helping her dad renovate her childhood home. Being a Los Angeles resident, Jessica spends a lot of her time looking for her next DIY project and sharing her love for home design.
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