The main parts of a masonry fireplace include a firebox, damper, smoke chamber with shelf and a chimney. Projecting into a room are a fireplace's mantel, lintel and hearth. Below the fireplace, usually in the basement, are the foundation and ash pit.
A fireplace built entirely of brick or stone can weigh several thousand pounds and needs a sturdy foundation under the whole structure to support the chimney. Inside the foundation is the ash pit, into which hot ash falls from the dump above. A door provides access to the pit for easy cleaning.
The firebox holds the fire, and during use, homeowners open the damper above with a lever or pulley to allow smoke to rise. Smoke flows into the smoke chamber and up into the chimney, finally exiting the building. Inside the smoke chamber, the smoke shelf captures large amounts of smoke before it funnels into the thin chimney.
The mantel, above the firebox and facing the room, provides decoration on modern fireplaces but was once helpful for reducing the smoke escaping the firebox. The hearth extends from the firebox into the room. It provides a safe structure on which to build a fire and prevents burning materials from falling into the home. The lintel, projecting downward under the mantel, adds structural support.