How to Identify Chimney Discoloration

Have you noticed any kind of discoloration on the outside of your chimney?  If you have, you may be seeing something that’s just a normal part of the “wear and tear” a chimney exposed to the elements goes through.  But discoloration could point to a problem that will become more serious over time if left unattended.

Below we’ll present a basic primer on how to identify chimney discoloration, but remember: it’s always best to have a professional inspect any issues with your chimney or fireplace.

White discoloration

It’s not uncommon to see the bricks of chimneys with white blotches or sections on them.  The scientific name for this is “efflorescence,” referring to the mineral salts that remain on the bricks when water evaporates.  Evaporated water is fine, but white discoloration may also indicate that water is entering the chimney through the bricks.

If there’s moisture or actual water inside the firebox, you know you have a serious leak.  However, it’s impossible for the average homeowner to determine if there’s a leak in its early stages.  For this reason, it never hurts to have efflorescence examined by a professional chimney sweep.

Green or black discoloration

Bricks with green or black discoloration may signal mold or algae growth.  Mold is hazardous to people’s health and will thrive in a moist environment.  If the bricks of your chimney are moist enough to grow mold, there may be a significant moisture issue within the bricks or inside the flue.  In this case, the mold needs to be removed and the chimney needs to be inspected.

Other black or brown discoloration

If they’re not mold-related, dark stains can have several causes.  Run-off from clogged gutters is one possibility.  A more serious concern is when the black or brown stains are the result of soot or creosote exiting the chimney structure.  Creosote is highly flammable, and if you see it on the outside of the chimney, it’s a call for immediate action to have your chimney meticulously inspected and thoroughly cleaned.

Dark outside stains also can result from a chimney fire that you didn’t know happened.  That’s right – there can be a fire in the chimney without you even knowing about it.  Fires that go unnoticed go out on their own.  But eventually there may be a fire that doesn’t go out on its own, and that can spell disaster.

Homeowners can perform regular visual inspections of their chimneys and spot certain problems.  If you notice discoloration of any kind, it’s important that you not try to “self-diagnose” the problem.  Discoloration is a sign that the chimney needs to be inspected by a certified professional, because letting it go will only lead to a worse problem.

Guardian Chimney Sweep of Houston is standing by to help with all manner of chimney discoloration issues as well as all other problems that affect chimneys and fireplaces.  We offer full-service inspection, cleaning, maintenance and repair.  Call us at (713) 401-2011 and tell us what’s happening, and we’ll tell you how we’ll address it.