SweepMasters Professional Chimney Services - Your Northern Virginia Chimney Sweep Specialists





Ash Pit
The cavity beneath the firebox, used as a receptacle for ashes and accessible via a cleanout door in the basement or crawl space.
Chimney Cap
A protective covering or housing for the top of the chimney intended to prevent the entry of rain, snow, animals, and birds and to help prevent downdrafts.
Chimney Fire
Chimney fires occur when combustible deposits (creosote) on the inner walls of the chimney ignite. A fire hazard exists if 1/4 inch of creosote (or more) coats the inner walls of the chimney. Failing to maintain your wood stove or fireplace properly can lead to a chimney fire.
Chimney Liner
A flue lining in a masonry chimney is defined as "a clay, ceramic, or metal conduit installed inside of a chimney, intended to contain the combustion products, direct them to the outside atmosphere, and protect the chimney walls from heat and corrosion."
Chim-Scan Video Scanning
A camera system that is lowered into the chimney (or pushed up from the bottom) used to inspect the chimney from a close-up range of just a few inches. The camera image is viewed on a TV monitor by the inspector. Video inspections may be recommended if the customer or sweep suspect certain problems. Video inspections are often recommended after a chimney fire or some other form of damage to a chimney, and are a routine part of a Level II or Level III inspection.
Clean-Out Door
That portion of the chimney located in the basement or at ground-level on the chimney exterior, used to remove creosote and other foreign matter from the chimney. The clean out door should be tightly sealed to prevent cool air from entering the chimney as this reduces proper drafting efficiency.
Creosote
Creosote is created by the incomplete combustion of firewood. Low fire temperatures cause incomplete combustion. Low fire temperatures can be the result of unseasoned firewood, wet or soft firewood, intentional burning of firewood at a low temperature, or closing the combustion air supply to the fireplace before all of the wood is consumed.
Crown
Also called a Wash. The top concrete portion of the chimney located at the top of the chimney that marries the brickwork with the flue tile and assists in shedding water away from the chimney. It can take the form of a sloped bed or a rectangular "formed & poured" shape.
Damper
The plate or valve that closes the fireplace flue when the fireplace is not in use.
Direct Connection
Direct Connection refers to how a lining system is connected to a wood stove insert. A direct connection is a lining system extending from the wood stove to the bottom tile liner in the chimney (generally in the smoke chamber).
Draft
The difference in air pressure at the same elevation between the inside and the outside of a chimney, chimney connector, or appliance. The term draft is also sometimes used to denote the rate of combustion air flow into a fuel-burning appliance, or the rate of flue gas flow.
Efflorescence
Efflorescence is a white stain that appears on bricks. It is due to moisture problems mixing with chlorides. It is an unsightly stain that indicates a problem with the chimney taking on moisture. Most often seen on chimneys venting gas appliances and is an early sign of deterioration.
Factory-Built Chimney
There are two basic types of factory-built chimneys: 1) metal factory-built chimneys and 2) modular/masonry factory-built chimneys. Metal factory-built chimneys are factory-made, field installed components that when used together properly form a complete chimney system. Modular/masonry factory-built chimneys are composed of factory-made, field-assembled components of pre-cast masonry materials. Both metal and modular/masonry factory-built chimneys should be listed according to Underwriters Laboratory (UL) standards and installed according to manufacturers instructions.
Firebox
The location in a fireplace where the fire is built and contained. It consists of 3 walls and a floor constructed of special firebrick and refractory mortar designed to withstand high temperatures. This is where the grate is placed.
Fireplace Door/Spark Screen
It is recommended that the height and width of the fireplace opening be covered with a screen and/or glass doors. Be mindful of the type of fireplace, though. Doors intended for a masonry fireplace CANNOT be installed on a prefab or factory-built fireplace. This will create a hot spot at the front of the chimney which can result in an unfriendly fire.
Fireplace Insert
Woodstove inserts are often installed in fireplaces to increase the amount of heat emitted into the home. It is important to note that fireplace inserts require the special installation of a liner system, as most fireplace flues are not intended to withstand the heat output of a woodstove insert. Consult a professional, CSIA Certified Chimney Sweep before purchasing a fireplace insert to assure a proper fit and proper installation of both the insert and its accompanying liner.
Flashing
A thin layer of sheet metal used to protect against rain or moisture. This layer is applied at joints where the chimney meets the roof, shoulder, etc.
Flue
The vertical passageway inside of the chimney that contains and allows the products of combustion from gas, oil, solid fuel, or fireplaces to pass out of the home and into the atmosphere. A chimney houses the flue. Flues can be made of terra cotta, clay tiles or metal.
Hearth
The floor area within the fire chamber of a fireplace or a fireplace stove.
Level I Inspection
A Level I inspection is the recommended level when an evaluation of the chimney system for continued service is needed and the conditions of use are not changing. This is usually conducted during routine or annual evaluations of the venting system , when an appliance connected to the system is being replaced with a similar appliance, or during chimney cleaning or sweeping. A Level I inspection is limited to readily accessible portions of the venting system, and accessible portions of the connected appliance(s) and the chimney connection. The inspector will check the readily accessible portions of the chimney, its enclosing structure, and the flue. A Level I inspection includes verification that the flue is not blocked or significantly restricted.
Level II Inspection
A Level II inspection is more detailed and thorough than a Level I inspection and is the recommended inspection when conditions of use for the appliance or venting system are changing, or when a Level I inspection reveals the need for a more detailed inspection. Several instances where a Level II inspection is specifically recommended include: Replacement of an appliance with one of dissimilar type, input rating or efficiency, Prior to a flue relining, upon sale or transfer of property, After an event likely to have caused damage to the chimney, such as a chimney fire or other sudden occurrence event. A Level II inspection includes all of the requirements of a Level I inspection as well as the following: Inspection of accessible areas of attics, basements, and crawl spaces, Accessible areas of the chimney exterior and interior, accessible portions of the appliance and chimney connection, Video scanning, or other thorough inspection, of the flue interior, evaluation of the flue lining to determine that its material and sizing is appropriate for the appliances being served, proper clearance to combustibles in the accessible areas listed above, proper construction and condition of the chimney system in the accessible areas listed above, while the Level II inspection is a rather thorough inspection and requires access to many areas of the building, it does not require removal of permanent parts of the building, such as siding, chase covers or wall coverings.
Level III Inspection
Level III inspection is the most detailed of all of the inspection types and includes inspection of concealed areas of the building. However, examination of concealed areas will be limited to areas reasonably suspected of containing hazards that cannot be evaluated otherwise. A Level III inspection includes all areas covered in a Level I and Level II inspection, and inspection of concealed areas to investigate known or suspected problems. In as much as certain portions of a Level III inspection require destructive action to the building, the inspector will discuss these areas with the building owner prior to the inspection.
Lintel
The horizontal architectural space between the fireplace opening and the damper.
Mantle
That part of a hearth setting that protrudes from the surface above the opening of the fireplace and is usually used as a shelf. If made of combustible material, it must be far enough above the fireplace opening to meet NFPA standards.
Masonry Chimney
Masonry chimneys are hand-built, field assembled chimneys which may be constructed of brick, concrete block, stone, or pre-cast material.
Parging
Parging is a layer of masonry that covers another surface. It is applied with a trowel, and can have a variety surface finishes.
Positive Connection
Positive Connection refers to how a lining system is connected to a wood stove insert. A positive connection is a lining system extended from the wood stove to the top of the chimney. This is the preferred method of lining a wood stove insert, and is required by code in most applications.
Scaling
Scaling is a condition wherein clay tile flue liners chip or peel. This is most often due to moisture mixing with corrosive deposits. Scaling compromises the integrity of the chimney liner and its ability to contain chimney fumes.
Smoke Chamber
The roughly-triangular space located above the firebox and at the throat of the fireplace leading up to the flue. This is the area where smoke gathers before it is exhausted up and out of the chimney. Because smoke tends to linger in the smoke chamber, large deposits of creosote often accumulate here.
Smoke Shelf
The ledge or concave shaped portion of the fireplace located directly behind the throat of the fireplace, at the base of the smoke chamber. The smoke shelf collects rain water, debris, or anything else that may enter the chimney. Considerable creosote deposits generally collect here.
Spalling
A condition of the chimney where the masonry work (brick or stone) begins to flake or peel from the surface. most often due to freeze/thaw cycles.
Throat
This is the narrow passage just above the firebox, forward of the smoke shelf and below the smoke chamber, that generally contains the damper.
Throat-Damper
Metal plate installed just above the firebox of a masonry chimney that is used to seal the flue shut when the fireplace is not in use.
Top-Sealing Damper
A device installed at the top of a chimney for the purpose of sealing the flue shut when the fireplace is not in use. They are often used as replacements for throat dampers that are installed just above the firebox when a masonry chimney is built.
Tuck-Pointing
Tuck-pointing is a masonry term that refers to repair of the mortar joints between bricks. When this mortar has weakened or started to fall out, bricks may become loose. Tuck-pointing refers to installing new mortar between the bricks.
Wythe
In a masonry chimney, it is a brick wall that partitions one flue from another inside the same chimney.
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