How it works

The cover is fabricated from sheet metal in a single piece or with welded seams, sized to overhang the chase by 1 to 2 inches with a slight pitch toward the front to shed water. A center hole or holes accommodate the chimney pipe penetration, and a storm collar wraps the joint between cover and pipe to prevent water from running down the pipe into the chase. Water management is the cover’s primary purpose, and a leaking cover saturates chase framing within months.

Galvanized chase covers fail by rusting through within 10 to 15 years, especially where standing water accumulates. The first signs are reddish-brown stains on the chase exterior, followed by visible holes, then framing rot inside the chase. Sweeps document chase cover condition during CSIA Level 1 inspections and recommend stainless or copper replacement before framing damage occurs. A cricket center peak prevents water pooling and significantly extends service life.

DFW context

DFW prefab fireplace chase covers from the 1990s and 2000s are now uniformly at end of life, with most galvanized covers visibly rusted or already leaking. The June 2025 hailstorms accelerated the failure pattern by denting and puncturing thousands of covers across Plano, Frisco, McKinney, and Allen. TSE fabricates and installs welded stainless or copper chase covers with center crickets, sized to the existing chase footprint, as a standard service for these neighborhoods.

Related terms

• [Chase](/glossary/chase/)
• [Storm collar](/glossary/storm-collar/)
• [Top-mount damper](/glossary/top-mount-damper/)
• [Prefab fireplace](/glossary/prefab-fireplace/)

Sources

• NFPA 211 (2024), Section 9.7
• IRC 2021, Section R1004
• UL 103 HT chimney standard