Ultimate Chimney Repair Term Guide

chimney repair terms

While interviewing chimney repair companies, many homeowners found themselves lost in a sea of technical chimney terms.  The chimney repair technicians use words like flue liners, corbelling and creosote as if homeowners use those words every day.  That fact is that no one but chimney repair techs uses those words.  Homeowners in the Washington DC Area tend to be smart people.  However, even the highest levels of education do not teach about chimneys. When providing services like ours, we do our best to share information using terms that are easy for homeowners to understand.  We have created this article to provide homeowners with all of the terms that they will likely need to make sense of the what the chimney repair tech is telling them.  Just take the time to read and digest each of them, and you will find yourself talking like a pro…or at least understand what they are saying. 

Chimney Repair Terms

Chimney

The chimney is the set of passageways to the exit points for flue gases. The chimney links the points of combustion to the exit point. So, flue gases from combustion get to the atmosphere through the chimney.

Ash pit

This is where ashes are stored. It is usually located at the base of the chimney. It is simply a pit where ashes are stored temporarily before being disposed of.

Baffle

This is an object that is fixed in any appliance to change airflow direction. The baffle also changes the direction of flue gases and also slows down air-fuel mixtures.

Chase

Chase is the area that surrounds metal flue pipes. It is used to stimulate a chimney. There are several variants of chase. Some variants are made of steel while some are made of wood. The external covering of chase made of either stucco or lathe.

Chimney Cap

Chimneys are installed vertically or almost vertically so that the exit point will be facing the sky. So, it is possible for rain, dust particles or snow to enter the chimney to through its opening. It is even possible for animals to get into a home through the chimney when not in use. This is why it is important for chimneys to have a protective cover to prevent the entry of animals, rain, snow and dust particles. The protective covering is the chimney cap.  You may want to read this article to learn more about replacing chimney caps.

Chimney Cleaning and Chimney Sweep

This term is easy to understand. It is exactly what you are thinking. Chimney cleaning is the process of cleaning the chimney. It is as simple as that. Soot, debris, and creosote usually gather in the chimney, and they can block the airflow when they become too much. In fact, the moment they start gathering there, the flow of air will no longer be seamless. So, the chimney has to be cleaned regularly for efficient performance.

Besides, it should be cleaned for safety reasons too. When soot and creosote encounter real heat, they can ignite resulting in house fires. The worker whose responsibility is to clean the chimney regularly is the Chimney Sweep. Learn more about our chimney sweep services here.

Chimney Connector

This is any of the pipes that connect the chimney to any fuel-burning device or appliance. They are usually more than one.

Chimney Liner

The flue system allows smoke and gas to travel from your fireplace up your chimney and away from your home.  The flue liner is the material that is used within the system.  Flue liners are commonly comprised of Terracotta made from clay. 

Corbelling

Corbelling is what happens when bricks are stacked on top of each other and are projecting outwards. This is often seen in the smoke chamber resulting in increased creosote build up that can result in chimney fires.

Creosote

These are highly flammable dark, tar-like deposits that form when products of combustion (smoke, gas, etc) fail to escape from the flue.  Instead of exiting the flue, they cool and form creosote. Creosote build up within the smoke chamber or flue is a common cause of house fires. 

Cricket

This is also known as a saddle. This is a long ridge that links the back of the chimney to the slope of the roof. The cricket is required when the chimney is 30″ or wider. Its purpose is to ward water off the main connection between the chimney and the roof.

Chimney Crown

A concrete surface that sits on the top surface of the chimney that sheds water away from the flue liner. There are several types f chimney crowns. 

Below are links to our 3 part series about chimney crowns

Part 1     Part 2    Part 3

CSIA

This abbreviation stands for Chimney Safety Institute of America. The organization is a non-profit making and tax-exempt organization established to regulate chimney and vent related activities in the United States. It is dedicated to venting and chimney system safety.

Damper

This is a valve that comes mostly in the form of a retractable plate. It is simply meant for controlling the flow of smoke or air or both. Most times it is located at the top of the chimney. It opens the top of the flue when the chimney is in use and it closes it when idle. This prevents cold air from coming in and it also prevents warm air that is keeping the house warm from flowing out through the flue.it is the cable attached to the side of the flue that opens and closes the flue.

Direct Vent

Direct vent” refers to a sealed-combustion system in which air for combustion is piped from the outdoors, and the event products are vented to the outdoors. (Got this from an online definition)

Draft

The draft is the pressure difference created by a rising gas. The pressure difference draws combustion air into the appliance and discharges exhaust gases to the atmosphere via the chimney

Chimney Flashing

Are metal strips at the base of the chimney as it penetrates the roof. There are two parts.

1- Base or step flashing, butts up against the chimney and is tucked underneath the shingles.

2- Counter flashing- over laps the base flashing and is tucked into the mortar bed joints of the chimney.

Flue

This is the link between the chimney and the exit point for gases. The gases from combustion pass from the chimney via the flue to the outside atmosphere. A multi-flue chimney is a single chimney that contains more than one flue.

Flue Liner

This is the inner wall of the flue. It is designed to hold products of combustion. It is done in adherence to the safety rules guiding the installation of chimneys.

Masonry Chimney

This is a chimney made of cement, concrete, stones, bricks or a combination of some of them.

Parging

This is a coat of mortar applied to a surface to smooth it out. Parging is often done in the smoke chamber to correct the corbelling bricks.  Some technicians use spray on substances to apply a thin coat to parge the smoke chamber.  This spray on technique does not last long.  The better chimney repair companies parge the chamber by applying thick coats by hand. 

Relining

Relining a chimney is the process of repairing/replacing damaged or faulty flue liners. It is the replacement of the flue liner.

Stainless Steel Liner

It is the stainless steel pipe used to replace a damaged liner in a chimney.

Soot

This can be described as carbon particle residue that is formed from oxygen-poor combustion. It resides inside the chimney until it is swept out. This is a regular occurrence. This is why chimneys should be cleaned regularly.

Stack Effect

This is the tendency of warmer air to rise within a chimney leaving cooler air at the base known as the stack effect. This is because air is lighter when warm or hot and heavier when cold.

Thermal Expansion

Thermal expansion is the expansion of the metal surfaces of the chimney caused an by an increase in temperature. This does not only happen in the chimney. It also happens everywhere else. Heat makes metals expand.

Thimble

This could be fixed/permanent or removable. It is the ring situated in the hole where the chimney is connected to the wall. The chimney connector passes through the thimble.

Vent

valuable is passage that links the flue collar to the draft hood.

Video Scan

This is not such a technical term. It is video camera and monitor that is installed to inspect the innermost part of the flues that are difficult to access.

Counter Flashing

This is the piece of metal that is placed in the masonry wall to ward off water from the wall and from the roof surface. Counter Flashing is important, as the continuous entry of water can cause issues. There are three basic types of counter flashing – surface mounted counter flashing, reglet counter flashing and through-wall counter flashing (SEE chimney flashing)

Tips for maintaining your chimney

Here are a few important tips for the maintenance of a chimney

It is advisable to use seasoned woods always. This is because using seasoned woods usually slows down the buildup of creosote. Properly seasoned wood should have a moisture content around 20%. The best way to ensure your fire wood is seasoned is by using a moisture meter.

Ensure compact stacking for your fire. It burns longer and more efficiently than loose stacking. You do not need starters like kerosene and gas to start a fire. Using any of them can lead to severe burns. Don’t overlook the importance of a chimney cap. Apart from protecting your chimney from debris, birds and some other small animals can enter through it when they are avoiding predators.

 

 

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