Chimneys deteriorate from the top down because of water infiltration. Harsh Northeastern weather patterns cause the crown to degrade as the concrete mortar slowly dissolves. The crown, also called a chimney wash, splay or capstone, is usually the first part of a masonry chimney to require repair. A bad chimney crown that’s neglected will inevitably lead to far more costly chimney repairs.

1. Most chimney crowns develop hairline cracks within a week of construction.
In this geographic area, water repeatedly enters the cracks, freezes and thaws.

2. After 15-20-years the hairline cracks will grow into deep fissures.

3. Water migrates through these fissures and the same freeze-thaw action attacks the underlying masonry. The mortar that binds the brick, stone or block develops cracks and gaps and now the sides of the chimney need to be re-pointed.

4. The freeze-thaw damage advances to the point where the underlying mortar no longer bonds the brick, stone or block together.

5. Because of the decayed crown, the homeowner will have to rebuild the uppermost 2, 3, 4 or more feet of the chimney, or begin wearing a hard hat in his own yard!

The above scenario highlights the need for regular chimney inspections; yet few homeowners have the means to inspect their chimney crown. The mortar decay we’ve outlined above is very common, and unavoidable in our harsh winter weather. The majority of the masonry chimneys we inspect are in either the second or third stage of deterioration described above. Fewer chimneys are in the fourth stage, but this advanced deterioration is too common in older homes. Very few chimneys we see are in the initial hairline crack stage.

While it’s sometimes necessary to totally rebuild a bad chimney crown, we’re usually able to economically repair it and prevent further chimney damage with Crown Coat brushable sealant. Crown Coat is a flexible waterproof coating that prevents water from seeping into the masonry below. It is specially formulated to withstand the severe thermal and weather conditions that confront chimneys and carries a 15-year warranty.