30 Sep How’s your crown?
Cracked and Missing Chimney Crown
The top of a chimney is called a crown or a ” wash” It is the most important part of the chimney when considering exterior maintenance because it is a collection point for water. If it does not have good integrity (ie. cracks, missing pieces) water will be channeled to areas where the masonry and flue liner will be vulnerable to the devastating effects of water entry and eventually freeze-thaw action. The freeze-thaw cycle does a lot of damage as water seeps into cracks and crevices and then sudden freezing temperatures (like overnight) cause that water to expand as it freezes. That expansion can push mortar right out of joints or spread cracks apart even further.
Chimney professionals use various elastomeric products that are especially formulated for chimneys to withstand temperature changes and cracks. Generally speaking and depending on your location, masonry repairs are best done in the spring through late fall. Under certain circumstances these repairs can be done in the winter season, depending on how mild the weather of the week is, among other things.
Shown below is a newly restored crown that will protect the masonry of this chimney from water damage for years to come.
Here is another before and after shot:
Chimney Crown Before and After