Efflorescence Chimney Attic

Efflorescence occurs when moisture moves through concrete or other masonry.

Efflorescence chimney attic.

There are two possible sources of the moisture. The efflorescence is formed when the chimney structure cracks has not been properly sealed or is missing a cap or other sealant. Efflorescence is a crystalline deposit of salts that can form when water is present in or on brick concrete stone stucco or other building surfaces. This allows rain water to seep into the brick or stone walls.

The minerals themselves do no harm. When the moisture evaporates minerals that had been dissolved in the water are left behind as a visible sign of the evaporation. Most of the time the rain will wash it away but sometimes it is necessary to remove tougher stains. As water moves through the wall it dissolves salt particles naturally present in the masonry along the way.

With today s high efficiency furnaces most of the heat goes into your home not the chimney producing a much cooler exhaust and leaving the chimney filled with cold air. The moisture picks up minerals carries them to the surface of the masonry and leaves them behind in the form of tiny crystals on the surface as the moisture evaporates. Cleaning efflorescence although rarely harmful efflorescence can still be unsightly on a chimney. You can simply brush them away.

Stains and leak damage to a chimney may be visible in the attic brown or black oozing stains may appear on both masonry chimney and metal chimney exteriors though if the metal chimney was properly assembled such leaks onto the metal chimney exterior surface are unlikely. Older furnaces required more chimney area due to their high rate of heat loss through the chimney and lower efficiency. The moisture which creates deposits on the chimney also adds moisture in the attic. A chimney sweep has chemical mixes designed specially for taking care of this problem.

If efflorescence is visible on your chimney it s safe to assume that there is more going on than staining.