Two Major Signs Your Chimney Has Moisture Problems

If you suspect your chimney is experiencing water leaks or problems, call today for an appointment!

If you suspect your chimney is experiencing water leaks or problems, call today for an appointment!

For those unfamiliar with these terms, let’s define them for you before we answer the questions.

Spalling: to break into chips or fragments; to chip or crumble
Efflorescence: a white powdery substance or incrustation

(We can almost hear you,“Ohhhh that’s what it’s called. We are familiar with the concepts, but never knew the proper name.)

Over the years Pozzi Chimney Sweep has been called to repair many instances of spalling and efflorescence. We know they are serious issues that need prompt attention by a chimney professional.


In her article on the, Marge Padgitt, Kansas City Alterative Energy Examiner, warns, “When chimneys spall, it is a sign of severe moisture penetration of the masonry bricks or stone. Spalling is the flaking off of a brick or stone surface, and is evident when the face of the masonry is missing. Pieces of bricks or stones may be found on the ground or on the roof, which is an indication that there is a problem”.

Too much moisture in the masonry is the primary cause of spalling. Chimney crowns that are not properly sealed, broken or missing bricks, soft porous masonry, and freeze/thaw/freeze cycles all contribute to the likelihood of spalling.

Excessive water and moisture are not a homeowner’s friend. Excessive rain, humidity, and freezing and unfreezing take their toll on masonry and cause spalling. While you may be tempted to use a commercial sealant to prevent water damage, if the source of the moisture is not eliminated, all you will do is trap the moisture…don’t be tempted! The damaged bricks must be replaced by a trained mason and the source of the leaks located and repaired.


Sometimes efflorescence is called “whiskers”. Salt deposits are the main component of the white residue. Why is this an issue? Because in order for the salt deposits to appear there must be water present, and like the situation with spalling, water is not a friend to your home. When efflorescence is on chimney bricks it could be from rain, but it could be coming from the warm air from inside the house forming condensation inside the chimney. Worse yet, the efflorescence could also be caused by a cracked or broken flue liner and gasses from your furnace. For an in depth explanation of efflorescence click here.

Whether your chimney is experiencing efflorescence or spalling, the result is damage to the brick and masonry of your chimney. Damaged chimneys cannot function properly and therefore put you and your family at risk for fires, toxic gas poisoning, increased heating bills, and structural damage to your home.

The Chimney Safety Institute of America (CSIA) recommends homeowners have a yearly inspection of their entire chimney structure by a CSIA certified technician. During those inspections, potential sources of efflorescence and spalling may be detected before you have major problems. If there is evidence of a problem your CSIA certified technician can make the necessary repairs to eliminate the influx of moisture and protect the integrity of your structures.

Pozzi Chimney Sweep is your go-to chimney contractor when it comes to chimney expertise in Northern Illinois. Call us for a consultation!

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