Chimney Chase Cover Installation and Replacement

Most homeowners don’t give their chimney chase cover a second thought until water starts dripping into their living room. By then, you’re looking at damage that could’ve been prevented with a $300 part.

Here’s what you need to know about that metal cap sitting on top of your prefab fireplace chimney.

What Exactly Is a Chase Cover?

A chase cover is the metal lid that sits on top of a chimney chase. If you’ve got a factory-built fireplace (the kind most homes built after 1980 have), you’ve got a chase instead of a traditional masonry chimney. The chase is basically a wooden frame covered with siding that houses your metal flue pipe.

The cover seals the top of that chase. Think of it like a roof for your chimney.

Without it, you’re letting rain, snow, and all that Kansas City humidity straight into the wooden structure. We get about 40 inches of precipitation a year here, and your chase cover is what keeps it from rotting out your chimney from the inside.

Why Chase Covers Fail

Most builders install the cheapest chase covers available. We’re talking galvanized steel that costs maybe $50. It’ll last about five to seven years before rust takes over.

The problem isn’t just age. Kansas City weather beats the hell out of these things. We’ll hit 100 degrees in July, then drop below zero in January. That expansion and contraction cycle cracks the seams. Add in our humid summers and those freeze-thaw cycles we get every spring, and you’ve got the perfect recipe for rust.

I’ve pulled off chase covers that were more rust than metal. The scary part? The homeowner had no idea until we pointed it out during an inspection.

Signs You Need a Replacement

Rust stains on the outside of your chase are the obvious giveaway. But here’s what most people miss: water stains on the walls near your fireplace or a musty smell when you haven’t used the fireplace in a while.

Sometimes you’ll hear dripping inside the chase during a rainstorm. That’s not normal, and it means water is getting past the cover.

The seams are usually the first thing to go. Look for separation where the cover folds over the edges, or gaps where it meets the flue pipe. Even small openings let in enough water to cause problems.

Material Options That Actually Last

Galvanized steel is cheap for a reason. Don’t bother replacing a rusty galvanized cover with another galvanized cover unless you want to do this again in five years.

Stainless steel is the upgrade that makes sense for most homeowners. We’re talking 304-grade stainless, which will run you around $250-400 depending on the size of your chase. It’ll last 20-30 years in Kansas City weather without rusting. The upfront cost is higher, but you’re done dealing with this problem for decades.

Copper is the premium option. It costs more—sometimes $500-800 for a custom fabricated piece—but it’ll outlast your mortgage. Copper develops that green patina over time, which some people love and others hate. Functionally, though, it’s bulletproof. We’ve serviced chimneys with 40-year-old copper chase covers that are still perfect.

The Installation Process

This isn’t a DIY job unless you’re really comfortable on a roof. Most chases require a ladder that extends at least 20 feet, and you’re working with sheet metal that catches wind like a sail.

A proper installation starts with removing the old cover and inspecting the chase top. We’re looking for rot in the wood framing, which happens more often than you’d think. If the wood is damaged, that needs to be rebuilt before the new cover goes on.

The new cover should overhang the chase by at least two inches on all sides. That overhang directs water away from the siding. We seal the edges with high-temperature silicone—not regular caulk, which breaks down from heat cycling. The flue pipe gets a storm collar and more silicone to create a watertight seal.

A good installer will also check the slope of the cover. It needs to shed water, which means a slight pitch toward the edges. Flat covers pool water, and that accelerates corrosion even on stainless steel.

What It Costs in Kansas City

You’re looking at $300-500 for a basic stainless steel replacement on a standard-size chase. That includes the cover, installation, and proper sealing. Custom sizes or difficult roof access will push that higher.

If there’s wood damage that needs repair, add another $200-400 depending on how extensive it is. Copper covers start around $600 installed and go up from there.

Compare that to the cost of fixing water damage inside your home. We’ve seen chase leaks cause $3,000-5,000 in drywall repair, mold remediation, and structural work. The cover is cheap insurance.

Maintaining Your New Chase Cover

Stainless steel and copper are low-maintenance, but that doesn’t mean no maintenance. Have it inspected annually as part of your regular chimney inspection.

We’re checking that the silicone seals haven’t cracked and that the cover is still secured properly. High winds can lift covers that weren’t fastened correctly. It takes maybe five minutes during a routine inspection.

Keep tree branches trimmed back from the chimney. We see a lot of covers with dents and scratches from falling limbs, and that damage compromises the protective coating on stainless steel.

When to Call a Professional

If you see rust, water stains, or any gaps around your chase cover, don’t wait. Water damage compounds fast. What starts as surface rust on the cover turns into rotted framing, which turns into interior water damage.

We service chimneys throughout Kansas City and the surrounding metro area. A quick inspection will tell you whether you need a replacement now or if you’ve got time to budget for it. Most of the time, we can install a new cover the same day we do the inspection.

Give us a call and we’ll take a look. Better to catch it early than deal with water dripping into your house during the next thunderstorm.