The chimney crown is the first line of defense against moisture and other degrading elements. It sits at the very top of the chimney, and sees the worst damage. It is also very difficult to reach. Homeowners typically must climb on to the roof of their home to get a glimpse of any cracking or discoloration, which are the most common signs of a moisture-infected chimney.
Not to be confused with effervescence, efflorescence is most often seen in the form of a white film that develops on the crown, as well as the rest of the chimney, as the damage travels. It doesn’t appear to be damaging, and it alone isn’t, but it is caused by water infiltrating the brick and mortar through porous holes that soaks moisture up like a sponge. The water shifts, freezes, and melts, moving around the salt that naturally occurs in the masonry. This shifting of water causes the patterns of white. Though, depending on different chemical components of the brick, it can also be green or brown in color. This shifting of water causes mortar joints to deteriorate and brick and concrete to come loose.
Similar to efflorescence in the cause, but water that creates an opening in the masonry can create a gathering of calcium compounds collected as the water moves through the masonry. These calcium compounds form a collection of white and gray crust that seems to drip down the side of the masonry. This will be found most likely on the brick itself.
Some coloring is a result of the brick composition itself. Lighter colored brick may show green and yellow stains easier, but they are also caused by water. This can be confused for efflorescence, as the white salt deposits can look very similar to the acidic solution of chloride salts. Manganese produces a brown or gray stain, but this one is more often attributed to the making of the brick itself and the firing involved that brings out the insoluble compounds that make the color.
Be aware of any rust-colored stains or fuzzy green stains especially. Rust colored stains can be a result of corrosion, and the metal parts of your crown may need to be replaced. Mold may look from far away to be efflorescence, but is a dangerous indicator of water damage. If you think you see this, call us immediately to check it out.
Seeing discoloration on your chimney crown doesn’t have to be scary. Give us a call if you notice something out of the ordinary. We also check the crown during our routine sweep and inspection, so don’t worry if you haven’t made it onto the roof recently! If you haven’t already made your appointment for us to come by in time for the new cooler season, don’t wait to get in the books! We want you enjoying your fireplace as soon as the weather gets that little nip in the air.