Chimney Stains? Here’s What They Mean

As a homeowner, you expect your chimney to become timeworn due to its exposure to the elements, but you don’t expect stains. Does your chimney have stains? Here’s what they mean.

Your Chimney has Black Stains

If you see black stains on your chimney, it could mean a number of things. The first possibility is that the black stains on your chimney were caused by soot. If you don’t regularly have your chimney cleaned, it can lead to a buildup of black soot. It may be that the chimney sweep who last cleaned your chimney did a poor job and incorrectly cleaned. It’s not unusual to see the interior of a home with soot stains if the fireplace was cleaned incorrectly, especially if it is an open-hearth fireplace. The soot stains are caused by a substance called creosote contained in the wood you burn.

The black creosote stains may be caused by using fresh or “green” wood that has not had time to cure. Using green wood along with an improperly cleaned chimney can lead to a catastrophe. Creosote is highly flammable; when it is built up in your fireplace, the chances of a chimney fire go up exponentially. It is imperative that you have the creosote removed from your fireplace and chimney to prevent a fire from happening.

Another possibility for black stains on and in your chimney is black mold. This type of mold is more common in humid locales but can also be found in homes that have higher humidity due to things such as saunas and Jacuzzis. If you have black mold in and around your chimney, there is a good chance a leak exists, and it needs to be inspected by a qualified chimney inspector. Black mold is not something you want to expose your family because of its many health-impacting issues. People with asthma or allergies are susceptible to black mold. The mold will need to be removed from your chimney by a qualified chimney sweep.

Your Chimney has Blue and Green Stains

These stains indicate algae is present on or in your chimney. It’s common to see algae grow where masonry mortar is being worn away, your chimney cap is compromised, or there is an area on the top of your chimney where water is ponding. While algae is less harmful to your health, it can be destructive nonetheless; it can wear down the mortar in your chimney over time and lead to leaks or even chimney collapse. As with algae and creosote, you should have a qualified chimney sweep remove it.

Your Chimney has Rust Colored Stains

Rust-colored stains are usually caused by, well, rust. It’s a sign that the chimney cap has started to rust, which means rust-colored stains streaming down your chimney. A rusting chimney cap also means that it has been compromised and can lead to a buildup of mold and algae in your chimney.

Your Chimney has Red Stains

Rust sometimes shows up as red stains, especially on metal siding or prefabricated chimneys. It’s self-explanatory when you see red stains on your chimney; something is rusting. The rusting areas could mean leaks if not dealt with right away.

Your Chimney has White Stains

A powder-like or salty white discoloration on chimneys is known as efflorescence. Efflorescence is the salt left behind due to moisture in your chimney evaporating. Many things can cause efflorescence on your chimney’s exterior, such as rain, sprinklers, and dew. If you find efflorescence stains on the inside of your chimney, then it’s most likely from a leak. As we discussed earlier, a leak in your chimney should be repaired right away.

In Conclusion

Stains on your chimney can mean many different things, and if you are unsure of what they mean, you should have your chimney inspected.

Chimney Saver Solutions Can Help Interpret Your Chimney’s Stains

There is no need to worry if you don’t know what discoloration on your chimney means; Chimney Saver Solutions can find the answer for you. Give us a call, and we will set up a time for one of our licensed chimney inspectors to come out and examine your chimney’s stains.