When people think of a chimney or fireplace, they often think of the firebox, but there are many components that make up the base assembly of a chimney and fireplace. When we speak of the base assembly, we are talking about the ‘foundations’ and ‘innards’ of a chimney system.

Inner Hearth

Technically, the inner hearth is part of the firebox. Its the part of the firebox where the fire goes, or the floor of the firebox. It is mentioned here because it often contains the Ash Dump Door.

Outer Hearth

Sometimes referred to as a hearth extension, this is an area in front of the firebox that is made of non-combustible materials. Its main purpose is to prevent any coals or logs that may roll out of the fireplace from landing on anything combustible.

Ash Dump Door

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

Ash Pit

A cavity underneath a fireplace firebox, used as a receptacle for ashes, and accessible for clean out by means of a cleanout door. The ash pit may be accessed either from the basement or from the first floor outside depending on the construction of your home.

Ash Pit Cleanout Door

A metal door located at the base of the chimney which leads to the ash pit, facilitating clean out of the ash pit. These doors may be either on the outside or inside of your home depending on your fireplace construction. You may have more than one door for chimneys that have more than one flue.

Two ash pit cleanout doors in the basement of a home. These doors provide access to the ash pit which is where ashes go when they are dumped from the fireplace above. These should be cleaned regularly.