White stains on a chimney are actually a type of residue called efflorescence. The white discoloration is not only unsightly, it is a symptom of moisture in the chimney system. Moisture is the biggest enemy to a chimney’s structural integrity. If efflorescence isn’t dealt with, the chimney structure could deteriorate and age prematurely.
More about Efflorescence
The formation of efflorescence occurs when soluble solutions move through bricks and other types of masonry and evaporate on the other side, leaving salt residue behind. It becomes a powdery or crystallized substance on the exterior of brick, block, or stone masonry. It can also have a fuzzy or fluffy appearance, over time.
Moisture enters into masonry for various reasons, such as:
When water moves through masonry, it dissolves the salt particles which are naturally present. After the water evaporates through the exterior wall, the salt residue known as efflorescence is left behind. The deposits of salt don’t actually cause any problems other than aesthetics. Removing the white staining is relatively simple as compared with other types of stains. The residue is, however, a clear sign of moisture in the chimney structure which can cause damage if not dealt with.
Efflorescence is usually white, but it is sometimes green, brown, or yellow. The type of salt in the masonry is what determines the color of the stain. Masonry can contain crystalline deposits of up to twenty different types of compounds. Salts which produce efflorescence are typically from sulfates of calcium, magnesium, potassium, sodium, and sometimes iron. The colors are created by the various kinds of minerals. Greenish stains are, for example, created by minerals containing magnesium as well as by molybdenum or sometimes vanadium.
Not every masonry chimney has the threat of developing efflorescence. The conditions which must exist for efflorescence to appear are:
Hazards of Efflorescence
Anytime efflorescence is evident on your chimney, you can be sure that there is more going on than premature deterioration of the masonry structure. The moisture which is creating deposits on the chimney is also adding moisture in the attic. Mold and rot will be created where the brick meets the wood, if the issue isn’t resolved. Other surfaces that can be affected by excess moisture are carpet, padding, and insulation.
Prevention or Repair
Consult a chimney professional to determine what type of repair is needed to resolve the moisture issue. There could be obvious problems such as cracks, missing mortar, or bad flashing. If the brick looks fine, all that may be needed is for the brick to be sealed; this will help, since brick tends to act like a sponge.
The best action to take is preventative action. Stop efflorescence before it ever forms by getting the masonry on your chimney sealed.
If you notice efflorescence developing on your chimney, call our chimney professionals today!
Chimney Solutions, Inc.
1155 McFarland 400 Drive, Alpharetta GA 30004