Our Company Blog

Identifying Chimney Discoloration

Stains on the sides of your chimney structure can take away from the curb appeal of your entire home. And while chimney discoloration can make your chimney look unsightly, it may also indicate a deeper chimney problem. The following are four of the most common types of chimney discoloration, what causes them, and how it could be affecting your chimney system.


Black and brown stains

Black and dark brown areas of discoloration on the inside and outside of the chimney are typically caused by soot. Soot stains are very common on older chimneys as well as those that have not been properly maintained.

Interior soot stains, especially those on the masonry directly above the firebox, are usually purely cosmetic. This kind of discoloration is most often caused by a lack of regular chimney cleaning, repeated use of green or unseasoned firewood, or a fire that was too large or otherwise out of control.

When found on the top and sides of the chimney, soot stains are typically the result of an excess of creosote in the chimney. Although creosote is naturally produced in wood burning fires, it can be made worse by allowing fires to smolder, burning green wood, or having a flue that is improperly sized. Because creosote is extremely flammable, it is important to have your chimney swept regularly – especially if black or dark brown discoloration appears.

Gas fireplaces and heating appliances should never have soot staining on the chimney. If this kind of staining is spotted on the chimney of a gas fireplace, it is important to stop using the fireplace and call a chimney sweep. Soot staining on gas fireplaces often indicates a malfunction or leak; this could lead to a buildup of dangerous gasses like carbon monoxide in your home.

Green stains

While it may be difficult to distinguish a dark brown stain from a dark green one, they have very different causes. Dark green discoloration n a chimney can be caused by algae and mold growth. This typically occurs when too much water repeatedly comes in contact with one area of the chimney, such as when a sprinkler repeatedly hits the same spot.

Red rust stains

Rust stains are commonly seen on homes with prefabricated or metal chimneys and can come in a rainbow of reds, browns, and oranges. This kind of discoloration is a sign that the metal chimney chase cover has begun to rust. If this type of discoloration is discovered, a chimney sweep should evaluate the condition of the chase cover before it is replaced to see if there has been any water damage to the rest of the fireplace and chimney system.

White stains

Powdery white stains on a chimney structure are a phenomenon known as efflorescence. Efflorescence a buildup of the mineral salt that gets left behind as ground and rain water evaporates. Exterior efflorescence is usually benign and can be caused by a number of sources including rain and sprinklers. However, if efflorescence appears on interior masonry, it is almost always a sign of an interior chimney leak.

Chimney staining and discoloration can be a black mark on your home’s beautiful exterior – literally. To diagnose the cause of your chimney discoloration and keep it from coming back, call the experts at Pristine Sweeps today.

The Importance of CSIA Certification

When it’s time to have the chimney swept, many homeowners choose to go with the least expensive company they can find. While this may save you a little bit of money in the short term, it may end up costing you more in the long run. Although a less expensive chimney sweep company can save you a few bucks, they may lack the knowledge, education, training, or expertise to correctly sweep or inspect your chimney system.

Instead of going with the least expensive chimney sweep – or the first one listed in the phone book – make sure to hire a chimney sweep with a CSIA certification. By hiring a CSIA certified chimney sweep, you can rest assured that you are working with a highly trained professional who understands that ins and outs of chimney maintenance and repair.


What is a CSIA certification?

The Chimney Safety Institute of America, or CSIA, was founded in 1983 as a non-profit organization with the mission “to advance public awareness while educating and certifying industry professionals”. Part of this mission included the creation of the CSIA certification. This professional designation for chimney sweeps represents the highest standards in the industry; chimney sweeps who have earned this certification have had to undergo a rigorous education, training, and testing process on many different topics in the chimney and fireplace industry. CSIA certified chimney sweeps are tested on information such as:

  • Current fireplace and chimney safety practices
  • Wide range of knowledge of fireplace and chimney building dynamics
  • Local building and fire codes
  • Maintenance and installation of heating appliances such as inserts and stoves
  • EPA standards for fireplaces, stoves, and other heating appliances
    Why is the importance of a CSIA certification?

Because the fireplace industry lacks many formal regulations, anyone with a chimney brush and a truck can call themselves a chimney sweep. However, uncertified chimney sweeps often end up doing more harm than good, doing little more than pushing the soot out of the chimney and into your home.

A certified chimney sweep can do much more than just remove the soot and creosote from your flue; because of their extensive education and training, they are often able to identify minor problems before they turn into major issues. This not only makes your fireplace and chimney safer to use, but can also save you money on costly future repairs.

How to find the right chimney sweep

Finding the right CSIA certified chimney sweep is about much more than a quick Google search or leafing through the phone book. Before hiring a chimney sweep, consider asking the following questions:

  • How long has the chimney sweeping company been in business?
  • Does the company offer current references?
  • Does the company have unresolved complaints filed within the city or state consumer protection agency or Better Business Bureau?
  • Does the company or individual carry a valid business liability insurance policy to protect your home and furnishings against accidents?
  • Does the company ensure that a CSIA Certified Chimney Sweep will be on the job site?

If you live in the Seattle area, trust the CSIA certified chimney sweeps at Pristine Sweeps to care for your chimney and fireplace system. Contact us today to schedule your next chimney services!