Commonly Used Terms for Your Chimney

Crown is the concrete at the top of a chimney. It seals off the air space between the outer walls of a masonry chimney and the flue liner. It slopes away from the liner and overhangs the chimney to shed water.

Splay or Wash is a mortar coating a-top a brick, block, stone or stucco chimney. A Wash keeps water from entering the chimney to prevent deterioration during the freeze thaw cycles. A Wash with cracks is the first point of water entry in any weather exposed chimney. Unlike a crown, a Wash is not concrete and does not overhang the edge of the chimney.

Flue is the passage in a chimney for conveying flue gasses to the outside air.

Smoke Chamber is the chamber in a fireplace directly above the smoke shelf and extending to the base of the flue.

Smoke Shelf is the area at the bottom of the smoke chamber and is the back wall of the firebox. The shelf is located at the intersection of the smoke chamber and the firebox. Typically there is a damper on the forward side of the smoke shelf.

Lintel is the horizontal non-combustible component, usually of masonry or steel, spanning the opening of a masonry fireplace to support the load above.
Ash Dump (Ash Pit) is an opening, usually with a hinge door and located at the bottom of the fireplace, where ashes can be dumped. Also , it can be the receptacle below the opening in which ashes collect before removal.

Damper is a valve, usually a movable or retractable plate, for controlling the flow of air or smoke.

Firebox is the section of a masonry fireplace that includes the firebrick, lintel, and damper. This is the combustion area of a fireplace where the fire is contained.

Firebrick is brick composed of clay and silica and designed to withstand high temperatures such as those found in a firebox.

Hearth is the floor area within the firebox of a fireplace or a fireplace stove.

Chimney Cap is the protective covering or housing for the top of a chimney intended for preventing the entry of rain, snow, animals, birds, etc., and for preventing downdrafts. Chimney caps are also called flue caps or rain caps.

Flashing is a sheet metal or other materials used in waterproofing roof valleys, hips, or the angle between a chimney and a roof.

Firestop is a horizontal fire-blockade constructed of non-combustible materials (usually sheet metal or gypsum board) and/or plywood of a minimum thickness.

Chimney is one or more passageways, vertical or nearly so, for conveying flue gasses from the appliance to the outside atmosphere.

Fireplace is the hearth, firebox (or similarly prepared place) and a chimney.