Anatomy of a fireplace

While there are differences among the various types of fireplaces, you will find several common parts. An understanding of the basic terminology is helpful. 

Outer hearth

This is the technical term for what we usually call the hearth. It is the part of the hearth that extends out into the room, beyond the fireplace opening. 

Inner hearth

The floor of the fireplace, inside the opening. 


This is where you build the fire. 


The rear wall of the firebox. 


A plate or valve that closes the fireplace flue when the fireplace is not in use. You must fully open it before lighting the fire. 

Throat damper

A damper located in the throat of the fireplace, just above the firebox. This is the kind found in most fireplaces, and is operated by means of either (a) a handle inside the firebox or (b) a knob above the fireplace opening connected to a rotating metal shaft attached to the damper.

Top-sealing damper

A damper located at the top of the chimney, operated by means of a cable extending down the flue to a handle in the firebox. 

Smoke chamber

The roughly-triangular space above the throat of the fireplace leading up to the flue. 


The vertical passageway up the inside of the chimney. 

Ash dump door

A metal door located in the inner hearth of some fireplaces, which leads to an ash pit. 

Ash pit

A cavity underneath a fireplace firebox, used as a receptacle for ashes, and accessible for cleanout by means of a cleanout door. 

Ash pit cleanout door

A metal door located at the base of the chimney which leads to the ash pit, facilitating cleanout of the ash pit.

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