Chase Cover - Metal Top Pan for Chimney Chase Guide
A chase cover is a metal top pan that seals the top of a factory-built chimney chase and sheds water away from the flue opening.
What It Is
A chimney chase is the framed, sided enclosure built around a factory-built metal chimney. The chase cover sits at the very top of that enclosure and acts like a roof for the chase, preventing rainwater from entering around the flue pipe.
Unlike a masonry chimney crown, a chase cover is typically made of metal and spans the full top of the boxed-out chase. It is a critical water-management component because leaks at this location can damage framing, sheathing, drywall, and fireplace components below.
Where It Is Used
Chase covers are used on prefabricated fireplace chimneys where a framed chase surrounds the vent or chimney pipe above the roof. They are common on wood-framed chimney structures finished with siding or stucco.
How to Identify One
From the roof, a chase cover looks like a flat or slightly sloped sheet-metal lid with a hole for the chimney pipe. Rust, ponding water, split seams, missing slope, and staining down the chase are signs the cover is failing.
Replacement
Replacement usually involves custom fabrication so the cover fits the chase dimensions, overhangs properly, and includes a raised collar around the flue opening. Stainless steel is often preferred because low-grade galvanized covers are prone to rust through.
Frequently Asked Questions
Chase Cover — FAQ
- What is the difference between a chase cover and a chimney cap?
- A chase cover seals the entire top of a framed chimney chase, while a chimney cap covers the flue opening itself. Many prefabricated chimney systems use both parts together.
- Why does a rusted chase cover cause leaks?
- Once the metal rusts through or loses its slope, rainwater can enter the chase around the flue opening or across the top pan. That water then runs into the chimney enclosure and nearby framing.
- What material is best for a chase cover?
- Stainless steel is usually the best long-term choice because it resists corrosion much better than light galvanized steel. Copper is also durable but used less often because of cost.
- Can a chase cover be repaired with roof sealant?
- Sealant can buy time on a minor seam issue, but it does not fix rusted-through metal or poor fabrication. A failed chase cover usually needs replacement, not repeated patching.
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