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Stainless Steel Chimney Caps: Everything You Need to Know

December 11th, 2023 | 5 min. read

By Louis Greubel

A Draft King stainless steel chimney cap sitting on a factory floor with industrial machinery in the background.

Steel is far and away the most common chimney cap material. At HY-C, we’ve made well over 1,000,000 chimney caps in the past few years, and literally 99.5% of them have been made of steel.

There are two types of steel that make up our chimney caps: galvanized steel and stainless steel. While galvanized steel is the more budget-friendly option, stainless steel is much tougher. It’s more robust, more corrosion-resistant, and it tends to stand up to weather and pests better than galvanized steel.

But what shapes and sizes do stainless steel chimney caps come in? Do they cover one flue, or are they capable of covering multiple flues? Are they customizable?

In this guide, we’re going to answer those questions and more. We’re going to cover everything you could possibly want to know about stainless steel chimney caps.

By the time you’ve read this guide, you’ll know all about the most common stainless steel chimney cap sizes and dimensions. We’ll even cover multiple customization options, all to help you find the right stainless steel cap for your chimney.

Stainless Steel Chimney Cap Sizes

Stainless steel chimney cap sizes are broken down into three groups: square, rectangular, and round. Here’s a breakdown of how many caps fit those three categories (out of all the stainless steel chimney caps we’ve manufactured in the past few years):

Stainless Steel Cap Shape Percent Manufactured by HY-C
Square 60.71%
Rectangular 35.57%
Round 3.72%

If you remember your high school geometry lessons, you know that all squares are rectangles, so we’ll talk about those two types together. And since square and rectangular stainless steel chimney caps make up over 96% of the caps we manufacture, we’ll cover them first.

Square and Rectangular Stainless Steel Chimney Cap Sizes

A square and rectangular stainless steel chimney cap sitting side by side against a white background

Stainless steel chimney caps are manufactured to fit specific flue pipes. Chimney flue pipes come in different lengths and widths, and we make our chimney caps to match the most common flue sizes on homes throughout the country.

When it comes to square and rectangular caps made of stainless steel, here are some of the most common sizes we produce:

Square and Rectangular Stainless Steel Chimney Cap Dimensions (inches) Percent Manufactured by HY-C
13 x 13 32.35%
9 x 9 30.45%
9 x 13 29.05%
13 x 18 2.75%
9 x 18 1.29%

As you can see, the three most common sizes — 13 x 13, 9 x 9, and 9 x 13 — account for about 92% of all square or rectangular caps.

The entire table accounts for about 96% of all the square or rectangular stainless steel chimney caps out there. If you have a square or rectangular flue pipe, there’s a very high chance that one of these sizes will work for you.

Other, less common sizes include:

  • 12 x 12
  • 18 x 18
  • 13 x 16
  • 11 x 11
  • 15 x 15
  • 5 x 9
  • 12 x 16
  • 13 x 20

Round Stainless Steel Chimney Cap Sizes

A round stainless steel chimney cap against a white background

Not all flue tiles are square or rectangular. Some are circular, and they’re measured by the diameter of the flue tile. Round flue tiles are a bit more varied than their cornered counterparts.

While five sizes cover most square and rectangular caps, eight sizes make up the bulk of the round stainless steel caps we make:

Round Stainless Steel Chimney Cap Diameters (inches) Percent Manufactured by HY-C
10 27.97%
12 17.57%
14 17.35%
8 10.14%
6 7.82%
9 4.31%
7 3.60%
13 3.04%

If you have a round chimney flue, there’s about a 92% chance that a stainless steel cap size in this table will fit your chimney.

Other, less common round cap diameters include:

  • 11 inches
  • 16 inches
  • 5 inches
  • 18 inches
  • 4 inches

Multi-Flue Stainless Steel Chimney Caps

A multi-flue stainless steel chimney cap installed on a chimney crown with tree limbs in the background

So far, we’ve only covered single-flue chimney caps — those that bolt directly onto one flue. Multi-flue chimney caps are a different animal. They’re made to cover two (or more) flues using just one cap.

Instead of attaching to a flue pipe, multi-flue chimney caps come with metal flanges at the bottom with pre-drilled holes. An installer uses these holes to bolt the cap directly into the chimney crown (the concrete layer that sits on top of the top row of chimney brick).

Multi-flue stainless steel chimney caps are much less common than single-flue chimney caps. About 95% of the chimney caps we make are single-flue, while the other 5% are multi-flue caps.

Still, the number of stainless steel multi-flue caps we make is well into the thousands, so they’re very much worth talking about — especially with regard to their sizes.

Stainless Steel Multi-Flue Chimney Cap Sizes

Multi-flue caps are measured similarly to single-flue caps: we measure the length and width of the flanges on the bottom of the cap (instead of the hood on top of the cap).

With that in mind, here are some of the most common stainless steel multi-flue chimney cap sizes we make:

Multi-flue Stainless Steel Chimney Cap Dimensions (inches) Percent Manufactured by HY-C
17 x 29 24.30%
14 x 26 15.43%
17 x 41 13.11%
17 x 35 8.91%
14 x 21 7.62%
14 x 34 4.30%
14 x 14 4.11%
14 x 30 3.39%
17 x 53 3.35%

These nine sizes account for about 85% of multi-flue chimney configurations, with 17” x 29” comprising about ¼ of the stainless steel multi-flue caps we manufacture.

Out of these nine common sizes, all of them are rectangular multi-flue caps, with the sole exception of the 14” x 14” size. Other, less common sizes include:

  • 17 x 17
  • 17 x 49
  • 15 x 37
  • 13 x 19
  • 17 x 58

Custom Stainless Steel Chimney Caps

So, despite the percentages, what if your chimney doesn’t fit any of the single- or multi-flue sizes we’ve mentioned so far?

To cover these rare instances, we manufacture custom stainless steel chimney caps. Specifically, we make two types:

  • Band-around-brick caps
  • Skirt-type caps

Because of the personalized nature of these caps’ sizes, there isn’t necessarily much data to share on their dimensions. But we can offer some insight to the caps themselves.

Band-Around-Brick Stainless Steel Chimney Caps

A Draft King custom stainless steel band-around-brick chimney cap installed on a multi-flue chimney.

A band-around-brick chimney cap is just what its name implies: the cap comes with an adjustable band that clamps around the top row of chimney brick when it’s installed.

The combination of this secure installation style and their stainless steel construction makes custom band-around-brick caps an excellent choice. We can even make these caps in standard sizes for people who want that extra bit of protection.

Skirt-Type Stainless Steel Chimney Caps

A custom skirt-type stainless steel chimney cap installed on a chimney against a white background

Stainless steel caps with a skirt are a tailor-made solution that offer even more protection than band-around-brick caps. These caps come with a skirt that covers the chimney’s crown, protecting it from precipitation to prevent cracking or wear and tear.

Like the band-around brick caps, we offer skirt-type stainless steel chimney caps in standard sizes for customers who want some additional protection. These caps may be more expensive up front, but they’ll help to save on expensive chimney repairs in the long run.

Should You Get a Stainless Steel Chimney Cap?

It should be pretty clear by now that chimney caps are a bit more than a hunk of metal that sits on top of your chimney flue. These caps are complex in their shapes, dimensions, customization options, and more.

Whether you’re looking to add a cap to your unprotected chimney or you’re replacing an older chimney cap, you may be asking right now, “Is a stainless steel chimney cap right for me?

The truth is, they’re not necessarily for everyone.

Black galvanized chimney caps outsell stainless steel caps by 3 to 1, mostly because stainless steel caps are more expensive and offer mostly comparable protection.

But if you’re looking for the most rugged, reliable solution that will withstand wildlife, weather, and everything in between for decades to come, stainless steel is the best choice you could make.

So, what if you want a stainless steel chimney cap?

Well, the first thing to do is to find the right cap size for your flue. Next, you’ll need to install your stainless steel cap. After it’s in place, the cap should last as long as you own your home, providing protection for your chimney and long term peace of mind for you.

Louis Greubel

Louis earned a bachelor's degree in English with a focus in rhetoric and composition from St. Louis University in 2017. He has worked in marketing as a content writer for over 5 years. Currently, he oversees the HY-C Learning Center, helping HY-C subject matter experts to share their decades of home solution products experience with homeowners and sales partners across the country.