Fireplaces

Fireplace Anatomy: Parts of Masonry & Factory-Built Fireplaces

Whether you have a traditional masonry fireplace or a modern factory-built unit, each component plays a specific role in how the system functions. This guide covers the key elements of fireplace anatomy.

Types of Fireplaces

There are two basic types of fireplaces: masonry and factory-built. A masonry fireplace is made from bricks, blocks, or stone and mortar, while a factory-built fireplace is made of metal and is composed of a metal firebox and metal chimney.

There are hybrid fireplaces, too, but these are the two general types. It’s important for you, as a homeowner, to know which type of fireplace is installed in your home.

Parts of a Masonry Fireplace

While this diagram covers all parts of a traditional fireplace and chimney made of masonry, the components described below are mostly part of the fireplace section for summarizing purposes.

Smoke Chamber

The smoke chamber is positioned below the chimney flue and above the damper. The walls of the smoke chamber slope, helping to compress combustion byproducts.

Smoke Shelf

A smoke shelf is located behind the chimney damper. The smoke shelf is flat and prevents back drafts from expelling smoke into the home.

Mantel

A decorative shelf or structure located above the fireplace opening. Today, it serves aesthetic and functional purposes, allowing homeowners to use it as a display shelf.

Damper

A damper is a set of doors that can be opened or closed. It is located at the top or bottom of the chimney flue. While closed, a damper helps to regulate airflow and protects your chimney from small animals and rain.

Throat

The throat is the narrow passage located just above the firebox and below the chimney flue. It helps in directing smoke and gases from the fire up into the flue.

Breast

The breast is the part of the chimney structure that projects out from the wall into the room. It forms the space around the fireplace opening.

Lintel

A horizontal support beam located at the top of the fireplace opening. It spans the width of the firebox and helps support the weight of the masonry or structure above it. The lintel ensures that the area above the fireplace opening remains stable and does not collapse into the firebox.

Firebox

The inner chamber inside a fireplace is called the firebox, and is where the fire actually burns. It is designed to withstand high temperatures and is typically constructed from firebrick or another heat-resistant material.

Inner Hearth

The floor area of the fireplace. The inner hearth is located inside the fireplace opening.

Outer Hearth

The fireplace outer hearth is the portion of the hearth that extends outward into the room from the firebox opening and inner hearth. It helps decrease the risk of fire.

Ash Pit Door

A small opening usually covered with a metal door, located in the inner hearth of the firebox. It provides access to the ash pit. This door allows you to easily sweep ashes down from the firebox into the ash pit, keeping the fireplace clean.

Ash Pit

The fireplace ash pit is a chamber located beneath the firebox that collects ashes and debris from burned wood.

Cleanout Door

An access point that allows you to remove ashes collected in the ash pit. This door is usually located at the bottom of the chimney structure, either inside or outside your home. Chimneys with more than one flue can even have additional cleanout doors.

Parts of a Factory-Built Fireplace

Source: JLC

Factory-built fireplaces are very complex systems with many components. Below you will find some of their most common parts, excluding the most obvious ones, such as the firebox.

Standoff

A standoff in a factory-built fireplace is a spacer used to maintain a safe distance between the fireplace unit and surrounding construction materials.

Gas Line

A gas line in a fireplace is a pipe that supplies natural gas or propane to fuel a gas-burning fireplace. Some wood-burning prefab fireplaces can include a gas line so that you can convert them to gas fireplaces.

Surround

The finished surface that frames the fireplace opening and covers the gap between the unit and the surrounding wall. It serves both a functional and decorative purpose by providing a clean, finished appearance while helping to protect nearby materials from heat.

Nailing Flange

The nailing flange is the extended part located on both sides of the unit’s face. It helps to secure the fireplace.

Frequently Asked Questions

Learn more about the components of a fireplace.

What Is the Hottest Part of the Fireplace?

The hottest part of the fireplace is the firebox, where the fire burns and produces the most intense heat. The amount of heat generated can vary depending on several factors, including the type of wood used, the design of the fireplace, and how well airflow is managed.

What Is the Lever on the Side of My Fireplace For?

This lever operates the damper, one of the most important parts of a fireplace. A damper is a hinged metal plate inside the chimney flue that regulates airflow. By pushing or pulling the lever, you can open or close the damper to control how air and smoke move through the chimney.

Should the Lever on a Fireplace Be Open or Closed?

Before lighting a fire in a wood-burning or gas fireplace, you should always open the damper to allow smoke and gases to escape through the chimney. While the fireplace is in use, the damper must remain open. When the fireplace is not in use, the damper should be closed to prevent indoor air from escaping and outside air from entering your home.

Install Your New Fireplace Today!

At Doctor Flue, we have been proudly serving Michigan and Ohio since 1986. Whether you need a fireplace installation, a fireplace facelift, or gas fireplace repair, our experienced team is here to help. 

Contact us online or call us at (800) 438-3583 to request a quote and learn more about how we can support your fireplace needs.

Call Us: 1-800-438-3583

Email Us: office@drflue.com

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