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Michaels Sheet Metal

Standard Gutter Size

Standard Gutter Size

What Is The Standard Gutter Size?

If you are planning on installing or replacing gutters around your home or place of business you might be wondering if there are standard size gutters and if so, what is the norm for gutter sizes?

While it might seem like a small component of a roofing system, the gutters and downspouts play a critical role in ensuring your home or commercial building remains weathertight and free of leaks. Gutters collect rainwater and snowmelt from your roof and direct it toward the downspouts that carry the runoff away from the structure and the foundation. As simple as that sounds, it is important that the gutter sizes are correct. Yes, there are standard size gutters, yet it is helpful to have your sheet metal or roofing contractor calculate which size best suits your site-specific needs.

There are certain factors that will dictate which standard size gutters are right for your home or building. You must take into consideration the pitch of your roof and the climatic conditions in your area. A gutter size that is too small might cause rainwater to spill over the edges of the gutter rather than drain toward the downspouts in a timely manner. Gutter sizes that are too large can be an unnecessary expense with little return on investment. So, let’s explore gutter sizes and types and how to choose the correct system for you.


Standard Size Gutters and Styles


For the most part, gutter sizes are either 5 inches or 6 inches. This is true for both half-round and ogee or k-style gutters. Half-round gutters are basically round-bottomed channels or troughs. Think of a metal tube or pipe that is sliced in half. K-style gutters have an ogee-style profile with a flat bottom. These are more decorative and fairly classic.

In the Los Angeles metropolitan area, 5-inch gutters are generally appropriate because of the drier climate. However, if the pitch of your roof is very steep, you might do well to have 6-inch gutters installed for those days when we do experience significant rainfall.

Michaels Sheet Metal is not only experienced in sizing gutters in Los Angeles. We also service Agoura Hills, Beverly Hills, Bradbury, Santa Clarita, Santa Monica, and South Pasadena.

Calculating the Appropriate Downspout and Gutter Sizes

Gutters are of no use without downspouts. Horizontal gutters are pitched to drain toward vertical downspouts. The downspouts carry the accumulated rainwater down and away from the house or building. This is critical for keeping water away from the foundation. Excessive stormwater near the foundation can cause settling and cracking. It is also important to carry water away from planting beds that can become saturated and suffer from soil erosion.

Calculating the Appropriate Downspout and Gutter Sizes

  • We’ll measure the length and width of each section of the roof to determine the total square foot area that will be exposed to stormwater.

  • We then determine the roof pitch by measuring 12 inches horizontally with a level from one edge of the roof. At the 12-inch mark, we measure down until a tape measure meets the roof surface. This gives you a pitch ratio, such as 6/12 or 5/12.

  • Next, we multiply the total square footage of the roof by the pitch to determine the overall surface area. We use a multiplier that directly relates to the pitch to come up with the total number.

Once the area and pitch total number is determined, Michaels Sheet Metal will recommend the appropriate standard size gutter. As a rule of thumb, if the total number is less than 7,500, we might recommend a 5-inch k-style gutter with a 3-inch box downspout. For anything over 7,500, you might be better off with a 6-inch half-round gutter with a 4-inch round downspout. Each building is unique, so we will make the best recommendation based on our calculations and the annual average rainfall in your location.

Gutter Materials and Thicknesses

We don’t simply figure out gutter sizes, we also help you determine what is the best material, metal thickness, and appearance of your gutters to match the style of your home or commercial building.

Our company specializes in standard size gutters as well as custom profiles. Our metals include aluminum alloy, copper, galvanized steel, stainless steel, and zinc. These sections are available in thicknesses ranging from 20-gauge to 32-gauge. Small gauge gutters are appropriate for drier climates, while thicker gutters are best for areas that receive significant rainfall or snow and ice.

Michaels Sheet Metal is a professional licensed sheet metal and rain gutter company with over 30 years of experience in the industry. We take pride in knowing that no two buildings are the same and strive for excellence by customizing gutters and downspouts without using pre-fabricated corners to perfectly match the unique conditions of your home or commercial building.

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