Chase Cover Replacement

The metal surface covering the top of a framed chimney is called a chase cover. It acts much like a roof for the chimney chase, helping keep rain, snow, ice and moisture away from the enclosed structure surrounding the fireplace and venting system.

These photographs show several chase cover replacement projects completed by AirPlease Missouri Chimney Services. The original covers had developed visible corrosion and deterioration after years of exposure to the elements. Rather than continuing to patch aging metal, the deteriorated covers were replaced with custom-fabricated stainless steel chase covers.

• Heavy surface rust and corrosion across the existing metal cover
• Rust developing around the perimeter, seams and edges
• Corrosion around chimney and vent penetrations
• Aging or deteriorated sealant around vent components
• Areas where water can collect or remain on the metal surface
• Rust staining beginning to travel onto the chimney chase or siding

Many factory-built chimneys were originally installed with galvanized steel chase covers. Galvanized steel uses a protective zinc coating to help shield the underlying steel from corrosion. Over time, constant exposure to rain, snow, humidity, temperature changes and standing moisture can wear away that protection.

Once the underlying steel becomes exposed, corrosion begins. This is when homeowners may start noticing orange or brown rust across the top of the chimney or rust streaks running down the exterior.

Rust is not only a cosmetic problem. As corrosion progresses, the metal can weaken and vulnerable areas can develop around seams, edges and penetrations. If water gets past the cover, it can enter the chimney chase where the damage may remain hidden from view.

Because many chimney chases contain wood framing and sheathing, prolonged moisture intrusion can contribute to deterioration of framing, sheathing, siding, trim, insulation, fasteners and other concealed components. Addressing a failing chase cover early can help prevent a relatively straightforward exterior replacement from developing into a larger water-damage repair.

For these projects, AirPlease Missouri Chimney Services removed the deteriorated chase covers and upgraded the chimneys with custom-fabricated stainless steel covers. Each chase is measured individually so the new cover is manufactured to fit the structure and accommodate the existing vent configuration.

Stainless steel provides substantially greater resistance to corrosion than ordinary galvanized steel and is well suited for a component that remains exposed to Missouri weather year-round.

• Superior resistance to rust and corrosion
• Long-term protection against water intrusion
• Custom fabrication for the individual chimney chase
• Proper accommodation of chimney and vent penetrations
• A durable, clean and professional finished appearance
• Reduced likelihood of future replacement caused simply by the cover rusting out

The material itself is only part of a successful chase cover installation. The cover also needs to be properly measured, fabricated and fitted so water is directed away from vulnerable areas instead of being allowed to collect on top of the chase.

Depending on the chimney, proper fabrication and installation may include custom measurements, perimeter overhang, finished downward edges, correctly sized vent openings, collars or flashing around penetrations, and appropriate sealing at applicable joints. A stainless steel cover should not only look good. It should fit correctly and manage water correctly.

• Visible rust or corrosion on top of the chimney
• Rust streaks running down the chase or siding
• Water entering around the fireplace or chimney
• Dripping sounds during or after rainfall
• Discoloration around the chimney chase
• A cover that appears bent, sagging or deteriorated
• Previous patching or excessive sealant around vent penetrations

Schedule an inspection with AirPlease Missouri Chimney Services. We can document the condition of the existing chase cover and explain whether repair or replacement is recommended.