Chimney Crown Failure in Wisconsin

•Causes and Prevention

Masonry chimneys in Wisconsin face extreme weather conditions, leading to premature deterioration. The top portion, or "chimney crown," is particularly vulnerable due to:

•Severe Freeze/Thaw Cycles: Wisconsin experiences more freeze/thaw cycles than any other US region, causing expansion and contraction of materials.

•Horizontal Surfaces: Water collects on horizontal surfaces, accelerating deterioration and erosion. •Inadequate Materials: Using mortar mix instead of Portland concrete reduces strength by 80%, making it more susceptible to damage/deterioration.

•Poor Construction Techniques: Failure to build a form and pour a 4-inch thick concrete crown with a 1- inch overhang and drip edge groove compromises structural integrity.

•Lack of Expansion Joint: Not installing an expansion sleeve between the flue tile and concrete crown causes damage from thermal expansion/contraction.

•Inadequate Reinforcement: Failure to add steel or fiberglass fibers to the concrete cap leads to cracking and deterioration.

•Insufficient Maintenance: Failure to regularly inspect and maintain the chimney crown leads to unnoticed damage and deterioration.

**Consequences of Chimney Crown Failure**

•Water leakage and damage to the chimney, roof, and interior of the home; •Structural compromise and potential collapse;

•Fire hazards and carbon monoxide poisoning risks.

***Prevention and Repair***

•Use Portland concrete for the chimney crown;

•Build a form and pour a 4-inch thick concrete crown with a 1-inch overhang and drip edge groove; •Install an expansion sleeve between the flue tile and concrete crown;

•Add steel or fiberglass fibers to the concrete cap;

•Regularly inspect and maintain the chimney crown.

****Wisconsin Building Code Requirements****

•Chimney caps must be at least 4 inches thick, slope outward, and have a 1-inch overhang and drip edge. By understanding the causes of chimney crown failure and taking preventative measures, homeowners and builders can ensure a safe, functional, and durable chimney.