Why White Staining on the Chimney Means Trouble
Have you ever noticed white stains on chimneys — perhaps on your own? Many of our chimney service calls from Madison, WI, to Galena, IL, and Dubuque, IA, involve problems caused by moisture; and stains on a chimney are a sign that moisture is permeating the masonry. The residue which causes the staining is called “efflorescence,” and it’s a sign of more trouble than a chimney with a diminished appearance.
Efflorescence is an indication that the structural integrity of your chimney may be compromised by moisture. Removing the unsightly residue isn’t terribly difficult; but if the underlying cause of efflorescence isn’t addressed, all kinds of trouble can occur, such as:
- The chimney could prematurely deteriorate;
- The chimney could begin leaning or could completely collapse;
- Moisture could enter the chimney and cause the flue lining to deteriorate, necessitating the purchase of a new lining;
- Moisture could enter the home and ruin ceilings, walls, carpets, and more.
What Causes Efflorescence?
Efflorescence is formed when soluble solutions permeate bricks and other kinds of masonry and evaporate on the chimney exterior, leaving a deposit of salt residue. Seen on the exterior of stone, brick, or block masonry, the substance is powdery or crystallized and, over time, can also appear fluffy or fuzzy.
Not all masonry chimneys develop efflorescence, even if moisture enters the masonry. Certain conditions must exist for efflorescence to appear, those being:
- There must be soluble salts in the masonry.
- There must be enough moisture in the masonry to create a soluble solution from the salts.
- The salt must be able to travel through the masonry and evaporate on the chimney exterior, leaving behind formations of efflorescence.
How Does Moisture Enter the Masonry?
The problem of white staining on the chimney all begins with moisture permeating the masonry. There are numerous reasons moisture gets in, such as:
- The absences of a chimney liner. (Water is a by-product of all combustion regardless of the fuel you burn)
- The lack of a chimney cap.
- A damaged or deteriorated liner or open joints between the liner section.
- The mortar has deteriorated and needs to be replaced.
- Bricks crack because of expansion or settlement of the structure.
Does the Staining Cause Damage?
The salt deposits themselves don’t cause any significant problems. And, actually, efflorescence isn’t always white. Sometimes the staining is brown, yellow, or green; it all depends on the type of salt contained in the masonry. There are up to 20 different compounds which can form crystalline deposits in masonry. The salts are usually from sulfates of magnesium, calcium, sodium, potassium, and iron. The color of the staining is determined by the type of mineral. Stains that have a greenish hue are created by minerals which, for example, contain magnesium.
Damage Associated with Moisture in the Chimney
If efflorescence is visible on your chimney, it’s safe to assume that there is more going on than staining. Premature deterioration of the masonry structure is occurring. The moisture which creates deposits on the chimney also adds moisture in the attic. Wood will rot and mold will be created where it meets the brick, if the issue isn’t resolved. Insulation can also be affected by excess moisture, as well as carpet and padding.
Repair and Prevention
Our chimney professionals can help you determine what type of repair is needed to resolve the moisture issue in your chimney.
One of the best actions to take is preventative action. You can stop efflorescence before it ever forms by having your chimney inspected to make sure its liner is in good condition and by waterproofing your chimney. If you live in the tri-state area encompassing Southwest Wisconsin, Northeast Iowa, and Northwest Illinois, contact us today for chimney cleaning, repair, and preventative maintenance.
For your Fireplace, Stove, Patio or Chimney needs
please call one of our Sponsoring Businesses.
Chimney Specialists, Inc
869 Main Street, Highland, WI 53543
Dubuque Fireplace & Patio
925 Century Drive, Dubuque, IA 52002