Chimney Cap: The Flue Cover
A chimney cap is a metal cover that sits over the flue opening — the hole where smoke exits. It has a solid top with mesh screening on the sides.
What it does: Keeps rain, snow, animals, and debris out of the flue while allowing smoke to exit. The mesh screening also acts as a spark arrestor.
Materials: Stainless steel (best value, rust-proof, lifetime warranty), copper (premium, beautiful patina), galvanized steel (budget, rusts in 5–10 years).
Cost in Chicago: $150–$700 installed depending on material and size.
Chase Cover: The Chimney Top Pan
A chase cover is a flat metal pan that covers the entire top of a chimney chase. Chase covers are found on prefabricated (factory-built) fireplaces — the kind with wood or siding on the outside instead of brick.
What it does: Seals the top of the chase enclosure to prevent water from entering. A chimney cap then sits on top of the chase cover over the flue pipe.
Materials: Stainless steel (recommended) or copper. Many builder-grade chase covers are galvanized steel that rusts within 10–15 years — the telltale sign is rust stains running down your chimney siding.
Cost in Chicago: $300–$800 for stainless steel replacement.
Chimney Crown: The Concrete Cap
A chimney crown is the concrete or mortar slab on top of a masonry chimney (brick chimney). It surrounds the flue tiles and sheds water away from the chimney structure.
What it does: Prevents water from entering the chimney between the flue and the outer brick walls. It should have a 2-inch overhang with a drip edge.
Materials: Concrete or specialized crown mix. NOT regular mortar (though many builders use mortar, which fails much faster).
Cost in Chicago: $400–$1,500 for repair or replacement.
Which One Do You Need?
Masonry chimney (brick): You have a crown and need a cap. No chase cover.
Prefab chimney (sided): You have a chase cover and need a cap. No crown.
Many prefab chimneys need both a new chase cover AND a new cap — especially if the original galvanized chase cover has rusted.
Not sure what type you have? A quick chimney inspection will tell you exactly what components you have and their condition.
Need Professional Help?
Widen Chicago provides honest diagnostics, transparent pricing, and expert service for every chimney and vent job. Same-week scheduling available.