What Are K-Style Gutters?

The letter K means many different things depending on the context. On a baseball scorecard, it represents a strikeout. On a stock sticker, it’s the abbreviation for the Kellogg Company. But what does it mean in terms of gutters?

Why Are They Called K-Gutters?

The term K-style gutters is derived from the profile of this type of guttering when viewed from the side. The outer shape of the gutter is supposed to (very vaguely) represent the letter K, as opposed to a perfectly-rounded, half-circle-shaped gutter. In other words, the outer edge consists of a short, straight line from the bottom of the gutter, then two opposing curves, followed by another short straight line. These gutters are also known as ogee gutters (interestingly, the word “ogee” means “double curve,” which looks more like the letter S.)

Like other types of gutters, K-style gutters are available in different sizes. The two most common sizes, as measured by gutter diameter, are five-inch and six-inch; though seven-inch, eight-inch, and custom sizes are obtainable from certain places. K-gutters are most often made with aluminum, though it is not uncommon to find materials such as vinyl, copper, and galvanized steel, which make up these products.

How They Differ from Rounded Gutters

K-gutters provide some distinct advantages over rounded gutters. First, K-gutters will hold more water than a rounded gutter with an equivalent diameter. Also, because of their unique shape, K-gutters are less likely to bend or protrude when impacted by force, which makes them stronger, even when lighter materials are used to produce them. However, K-gutters have more sharp edges on which debris can catch or accumulate, and they are also harder to clean than their rounded counterparts.

Why Are They Popular?

There’s another reason why K-style gutters are the most widely-used gutters in America. That’s because when you look at K-gutters on a house or structure, they somewhat resemble the stylish crown molding that is found on interior ceilings. Therefore, builders tend to select K-gutters because their profiles blend better with modern architectural trends.

Because of their popularity, most gutter manufacturers have standardized the K-style profile in their gutter-making machines. Many contractors have portable gutter-making machines which enable them to feed in aluminum sheets to be fashioned into seamless K-gutters of a predetermined length. On the other hand, K-gutters are commonly found in 10-foot sections in hardware and home improvement stores for do-it-yourselfers who want to purchase their own materials.

The price of K-gutters largely depends on their base material and their length. But because they are found on the majority of buildings in the U.S., K-style guttering is usually the default choice for contractors and building suppliers. However, many different gutter styles will transport runoff water just as well—so homeowners need to decide whether K-gutters are right for them.

Dimensions for Standard K-Style Gutter Sizes

In sizing rain gutters, the following consideration is important. Currently there is no standard in the roof drainage industry but these concepts are based on handed down experience.

Outlet Sizing and Spacing your gutter system will perform its best when a proper outlet size is chosen to drain a given roof area. Downspout sizes must not exceed the bottom width of the gutter. Furthermore, the standard norm for gutters among many in the rain carrying industry is to allow 1 square inch of outlet opening in the gutter for every 100 square feet of roof area being drained.

Roof Slope Rainwater must not overrun the front edge of the gutter. A steep pitched roof can accelerate rainwater velocity. The gutter must not be hung too high or too low against the fascia or eaves of the roof.

Gutter Slope To allow for proper drainage in gutters, allow the gutter to slope approximately 1/4″ drop every 10 feet toward the downspout for adequate drainable. To prevent mosquitoes, your gutter system must not hold rainwater.

Gutter Style gutters are typically K-Style and Half-Round Styles though custom profile is available. K-Style sizes will typically range from 5″ to 6″. 7″ and greater are appropriate for churches and larger commercial buildings. As a general rule, recommends for roof areas that exceed 2800 square feet, a 6″ K Style size with a 3″x 4″ downspout size would be appropriate.

Metal Corrosion Issues all gutter and components must be the same to prevent electrolysis or electrical corrosion. See ‘Galvonic Corrosion’ for more detail.

Please note that our aluminum K-Style Gutter is Hemback Style. Copper, Galvanized and Painted Steel are Straight Back Style. All K Style Gutter is Roll-Formed.

E = This number identifies the accepted industry size description of the K gutter even though actual K-Style gutter profile sizing may slightly vary depending on who is the gutter forming machine manufacturer.

Most residential gutters come in two sizes– 5″ and 6″ –and are made of either aluminum, steel, zinc, vinyl, or copper in a standard “K” style.

The typical 5 inch K-style gutter comes with 2 x 3 inch downspouts. A larger residential gutter system would consist of 6 inch K-style gutter using a 3 x 4 inch downspout.

K-Style Gutters

K Line Gutters

One foot of 5″ K-Style gutter holds 1.2 gallons of water. One foot of 6″ K-Style gutter holds 2.0 gallons of water. For commercial applications, box gutters, can be made in 7, or 8 inches or even larger custom sizes that hold even more water.

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