Crown cracking occurs from moisture being absorbed by the crown and then freezing. The freezing expands the moisture and evently will produce cracks in the crown. All crowns in the Chicagoland area will crack, it’s just a matter of when. The problem with cracks is they allow moisture to run through them into the chase. When moisture gets into the chase, it attacks the mortar joints from the inside which can’t be seen from a normal Level I Inspection.

The above crown cracks were fixed using Crown Coat with a 15 yr warranty and a 12″x12″ stainless steel chimney cap was installed to keep rain, snow and animals out of the flue.