What is that White Stuff on my Chimney?

Have you happened to spot a chalky, hazy white coating on the bricks of your chimney? You may have thought of it as something that happens to all aging chimneys, or perhaps you believed it to be a type of mold growing on the surface. Actually, the white powder is a common problem called efflorescence—sometimes referred to as “whiskers.”

Efflorescence is composed of crystallized minerals. It is caused by water leaking into your chimney system and then evaporating. Bricks are naturally quite porous and can absorb a large amount of water—similar to a sea sponge. The moisture brings salt deposits to the surface of the bricks, which are left behind as the water evaporates.

In and of themselves, these salt deposits do not warrant much concern—still, they potentially are indicative of a more serious issue with your chimney. Moisture can damage and deteriorate the chimney’s structure. The dampness can act as an excellent place for mold to flourish, as well as other moisture-induced problems.

There are a number of reasons why efflorescence may be present on your chimney. First, it can be caused by a missing chimney cap. If your chimney has no cap upon it, water-soluble salts can easily get into your system. Second, a failure to properly seal your chimney can lead to a layer of efflorescence. Finally, if your chimney is cracked, the cracks provide a path for water to flow into the structure.

Now that you have a little background on efflorescence, what can or should you do? While you may have a general idea of its causes, you should still first hire a professional, certified chimney sweep to inspect your structure. A chimney sweep can properly inspect the interior and exterior of the flue, searching for any existing structural damage or areas where the sealant is lacking. After the inspection, the sweep will provide a report to you on the conditions of your chimney, along with solutions for any issues. The remedy may be as simple as the replacement of sealant, or as complicated as complex structural repair.

If you have noticed efflorescence on your chimney and would like to hire a professional chimney sweep to inspect, please give Bob Davis Chimney a call today!

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