Which of the following is NOT a common problem associated with masonry chimneys?

The assertion that a masonry chimney should be continuous through the roof is based on standard building practices. A properly constructed masonry chimney typically extends above the roofline to ensure proper ventilation and safety for the building. If the chimney is not continuous through the roof, it indicates significant structural or design flaws that could lead to inefficiencies or hazards. Therefore, this option is correct in identifying a scenario that is not common or acceptable in masonry chimney construction.

In this context, the other options are associated with potential issues commonly found in masonry chimneys. For instance, improper anchoring can lead to stability concerns, while cracks in the mortar can signal wear, water infiltration, or structural issues. Excessive creosote buildup is related to the combustion process and affects the chimney's performance and safety. By focusing on the requirement for a chimney to be continuous, the answer accurately identifies an important structural element that must be adhered to in compliant chimney installation and construction practices.