Q: Dear AsktheChimneySweep,

My name is Rick and I’m from Illinois. After having my yearly chimney sweeping and inspection, the serviceman says that the chase cover has rust and needs to be replacing. I didn’t get a chance to ask him what this meant, he just left the invoice in the door with the recommended repair listed. I don’t even know what chimney chase covers are, is this is crucial fix? Money is short right now. – Rick

A: Rick,

You wouldn’t know it but in this profession we see a lot of rusted out chase covers. My guys write estimates for replacing a chimney

Chimney Chase Cover Water Problem
This chimney chase cover allows water to pool instead of run off the sides.


chase cover a few times a week. The chase cover, also known as the chase top, is the cover that protects the top of your chimney. This is to keep out the elements and critters. It fits over the top of the chimney like a lid. The chimney flue pipe extends up through the middle. What has likely happened is that the chimney chase cover was allowing water to pool. As a result it became rusted. Chase cover are usually steel which is prone to rust. This isn’t necessarily a pressing repair, but you should take care of it in a timely manner. The rust damage will continue to worsen until holes form and water penetrates the chimney’s flue.

Bad Chase Covers Leads to Water Damage

Water damages almost all kinds of chimney covers including chimney caps and the chimney crowns. When it comes to caps or chase covers, I always recommend stainless steel. The extra cost of installing a stainless steel cap or chase cover over galvanized steel is completely worth the extended lifetime of the cap and additional reliability that you also receive. Rick, when you do decide to replace your chimney’s chase cover, elect for a stainless steel version. Although rust stain removal is not extremely difficult, the metal is weak so replacement is definitely the best option.

Other times, rust problems are worsened by a poorly designed chimney chase. The chimney chase should be designed such that it sheds water from the chimney and does not allow it to pool. As a rule, if water is allowed to pool anywhere, whether it be on top of a chimney crown or on top of brick or anywhere else, a water problem will ensue. The chase should actually be constructed so that there is a little bit of a slope from the middle, where the chimney’s flue will stick out, down to the sides. This will allow water to run off of the top of the chimney and prevent premature rust problems.

Chimney Chase Covers

Chimney chase covers come in different designs based on how many flue systems are being vented through your chimney. There are chase covers available with two or three holes for multiple flues and chases where the hole is off center for specially designed chimneys. There are many custom chase cover manufacturers who will design your chase cover to your exact dimensions. You want to make sure that you are taking accurate flue diameter measurements during this process as well.

Rick, as I said before, I would definitely not let this problem go for too long because rust stains are more than just unsightly, once water is able to enter the chimney you experience more problems will surely begin to occur. Make sure you are choosing a quality material and that the chase cover is sloped downward to prevent water from pooling.

Clay Lamb
Latest posts by Clay Lamb (see all)

25 thoughts on “Chimney Chase Covers

  1. I was told I need my chase repaired. He will put down new stainless steel and seal with a rubberized sealant. He will also replace a missing 6″ cap. He is charging $1200 for the job which he says is a huge savings over replacing the chase completely—$2400
    I told I’d let him know…Is this a fair price for this repair?
    I have a Heatilator fireplace and I would say it is a standard size unit.

  2. When questioning a price it is a good idea to get 3 or 4 estimates and evaluations, from reputable contractors. I found that the majority will have a common persuasion and help narrow down your selection. Always check for references.

  3. I’d check out Chimney Liner Depot. Buy your own stainless steel custom made cover and install it yourself. You can call them, they’ll talk you through getting the correct measurements, and fabricate your cover for you. You won’t pay ANYWHERE near $1200 for it.

  4. But someone has to climb up there, take the measurement and climb up there again to install it. With chase covers you have to do this twice! (without Workers compensation). Most customer can’t clean their own gutters or put up Christmas lights without fear of falling off of the ladder.
    I always tell the guys don’t take it for granted, what you are able to do today while your young and comfortable on the roof top

  5. $1200.00 for a stainless steel chase cover is not outside of the realm of possibility, it really depends on how long and wide, how many holes for flues to come through it, size of the drip edge, if you need storm collars or not and caps.

    You may think you’re very good at taking measurements and you very well may be, however I have had at least a dozen customers call me in after they “Measured their own chase cover” after getting estimates they thought were too high, Purchased the chase cover and tried to install it only to say they got up there no problem to measure but doing it with the chase cover in hand was impossible and changed their minds,so they called us to install it only to find out their holes were 2″ off center or worse in one case , not even close ! and the company they buy the chase cover for is not going to take it back once it is made it is sold case closed so then they’re stuck with purchasing the chase cover all over again and they’re stuck with a 600 dollar piece of scap stainless worth approx 20 bucks, trust me when I tell you it is not as simple as it sounds to take the correct measurementsif you make the hole the same size as the flue it will not fit always give yourself at least 1/2 inch play, install a collar and a storm collar and the 1/2 difference you’ll never even notice. The very most I have ever done a chase cover for was 3000 but that was an absolute monster with 3 rows of 7 10 ” holes! In a bulding across the street from Central park in Manhattan thinking back about that , I even went a little low just to get the job because I wanted the rest of the chimneys and there were many but that is a different story entirely 🙂 and when in doubt just let a pro do it, it will cost a little more but if he messes it up he will be responsible for ordering another chase cover but if he’s worth his weight in dog dung, it will be spot on . . Best of luck to you all. Oh and a word of advice, if you hear a grinder going when that chase cover is being installed make sure they are not cutting the hole larger because they screwed up with the measurments , I have seen where “Custom chase covers were mis measured and the guy didn’t want to buy another chase cover so they just attempted to open the hole larger and that is NOOOOOOOOO GOOOOOOOOOD, then they seal around the guys brand new chase cover with TAR !!!1 OMG are you frigging kidding me ?

  6. Rick,

    You ask if it is a crucial fix. I would consider it a crucial fix if you have water leaking through and damaging the inside of the chase and flue. This could lead to bigger problems down the road.
    I hear you when you say money is tight. I installed this myself and saved a lot of money. I’d recommend Rockford Chimney Supply, I did the price checking and they were most reasonable. Hope this helps.


    – Matthew

  7. Chase covers are most definitely a common problem because the home builders make them from sheet metal which rust. The average cost to replace a chase cover, at least for my company is between 800-1200 dollars, depending on the roof pitch, height ect… Although I have charged more and less for some. Always make sure whoever is replacing your chase cover uses stainless steel, with a drip edge on the skirt, 2-3 inch collar and cross brace. So the water does not puddle on top.

  8. Sorry for the late reply Barbra, my vacation got in the way. This type of construction for us would depend on how stable or damaged the original brick chase is today.
    We will often build on top of a chase after removing damaged corse (rows) of bricks. Get 3 o 4 prices from contractors. I would recommend either members of the National Chimney Sweeps Guild or solid contractors with a proven track record on AngieList or another contractor reference provider. Think about requiring brick matching and mortars coloring prior to construction. You can find a reputable Chimney Sweep in your area by using this link to the National Chimney Sweep Guild locator : http://www.ncsg.org/search. Because this can be such a major investment into your home, be sure to go online and read their customer reviews from Google, BBB and AngiesList. Do not be impressed with those cheaper companies without “recent references” of masonry work of like and kind “that they” have completed.
    https://youtu.be/IzVfVpOE7m <------ Chimney Rebuild https://youtu.be/S6n1kn_hCoA <------ Cut and plug Brick Replacement https://youtu.be/FfEtBmStMdg <------ Chimney Crown Repair

  9. We have a chimney leak and have been told it is our chase cover. One recommended the stainless steel chase cape. The other company said they would not replace it but cover the current chase cover with an Elastic Coating (3 coats). I have photos of the chase cover but not able to send them through this link. What is your opinion on the elastic coating. Also this company suggested an aluminum chase cover. We live in Louisville, Ky.

  10. Heather, I have not used any type of elastic coating on a metal chase cover. I have had a lot of experience solving water problems with stainless steel chase cove replacements.
    Please watch the attached video as I feel it will help you in your decision. For me I would select stainless and be done with it. Be sure request that it has the proper metal breaks or folding creases. These will strengthen the chase cover shape, while at the same time slightly push the snow an water off of it. Also the collar needs to come up around the chimney flue pipes as shown in the video.
    Stay dry, your home will love you for it!

    Chimney Chase Covers

  11. Hello! I have a rusted galvanized steel chase cover on my wooded chimney but with no leaking holes. Is it totally stupid or reasonable to try to save the current one with any kind of coatings or piant primers on it, instead of replacing it with a stainless steel?

  12. For me it is a matter of design, the chase cover design might be a little more important than the material that we are using. There are a lot of great paints and primers out there and if you feel that you can clean up the chase cover and repaint it properly I would say go for it. When you have time watch this video, at 1: 33 I start to talk about “Cross Breaks”. Also I address the chase pan corners and most importantly the flue pipe collar design that needs to come up out of the chase cover and will be fitted around the chimney pipe. Years ago a good friend of mine taught me when he is faced with the decision between “Low Maintenance and No Maintenance” that he always tries to go for ? “No Maintenance”, then as we age we’re not regretting and thinking, do I have to do that again ? . . . just food for thought.
    Know your limits and be very careful on that rooftop!
    Lee, thanks for stopping by here at Ask the Chimney Sweep


  13. What would it cost to replace a chimney chase 37.5″×75.5″ and chimney cap that is two in. Off center?

  14. Jade, for me it’s never just about the price, it most often is about the real value. It has been my experience that an average stainless steel chase cover will run between $800-$1500. For us pricing is first based on the degree of difficulty to install that chase cover, as well as the size and shape, and how many holes or penetrations that are needed. I would recommend contacting two or three chimney contractors in your area. Here is my video link to learn a little more about Chimney Chase Covers. Also here is a link to the NCSG national chimney sweep guild to help you find a chimney contractor.
    Before signing a contract, take some time to look at your contractors websites, as well as reading any online reviews about their work.



    Hope this helps!

  15. Hi, I’m dealing with a furnace part on top of the roof that is rusted and is crooked. It measured 17″ squared. Its made of metal and it looks like brick. Do I call a furnace company or a roofer? I didn’t measure the height but can if needed. I have no idea what its called. Any insight would be a big help, thank you very much. Sincerely, Mike

  16. Mike it is a metal chase. When we run into these we disassemble the chase and take it it to a metal and have it duplicated and then reinstall it. (I would recommend using a metal that is treated for paint grip of some type.)

  17. Has anyone used a fiber aluminum roof coating on a chase cover. I have a rusted cover, in good shape, but bleeding rust down my siding. I am just looking for options to painting.

  18. My recommendation would have a brand new stainless steel one put on. then you don’t have to worry about it for years, you can sit in your rocking chair and look at it for twenty years. but if you’re gonna go your route, I don’t think youre off course, I just wouldn’t do it. I wouldnt take my time coating that, respectfully.

  19. I was wondering how much of my flue pipe should be extending up past the chase cap. I cant seem to find an answer

  20. I had a galvanized chase cover that had rusted. I hired a contractor to do various repairs to my house including replacing the chase cover and cleaning the rust off brick. They measured and ordered a stainless steel cover and have installed it. Looking at it from the ground it appears to be to big it overhangs about 2″ away from the brick on one end. Is this normal? I thought it was supposed to fit tight over brick.

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