Steps Toward Choosing Proper New Rain Gutter Size, Part 1

If you’re looking for an efficient, modern upgrade to your water drainage system, the pros at Wizard Rain Gutters are here to help. We offer rain gutter replacement, repair and numerous related services, ensuring your roof and entire structure are properly draining to the right locations to keep your foundation and siding intact.

When considering a new rain gutter installation, perhaps the single most common question from our clients is a vital one: What size should my new gutters be? This two-part blog will go over everything you need to know in this area, from the popular gutter sizes typically available today to the calculations you or our team members will need to make to determine your optimal sizing needs.

choosing proper rain gutter size

Popular Gutter Sizes

Generally speaking, two gutter styles are most common in standard US homes today: K-style five-inch gutters, and half-round six-inch gutters. For the vast majority of homes, one of these two sizes are easily large enough to cover all the drainage needs present.

In certain cases, however, roofs may require additional downspouts or even possibly wider gutters than normal. This is sometimes the case when a house has a large, steep roof that carries lots of water, or in areas that experience major rain and snowfall each year.

Drainage Area

As you look to determine which size is right for you, the first consideration to keep in mind is the square footage that makes up your gutters’ drainage area. In cases of standard gabled roofs, present on most homes, you just need to calculate the slope of each side of the roof – nice and simple.

In cases where the roof has multiple facets, however, each individual surface area will need to be calculated separately. From here, you can add them up and get the entire square footage that needs to be covered. In these cases, our team will be happy to help you with your calculations.

Roof Pitch

From here, it’s time to consider the roof pitch factor. This refers to how steep your roof is – the steeper the roof, the more rain that will be collected, especially when it’s windy.

To measure roof pitch, a two-foot level and a tape measure are required. Keep one end of the level against the roof, level it, and then measure the distance between the middle of the level and the roof under it. This measurement is known as the “twelve-inch run” – an eight-inch gap between the underside of the level’s midpoint would be called an eight-in-twelve pitch. From here, roof pitch factor is determined using this list:

  • 12-in-12 or higher: 1.3 roof pitch factor
  • 9-in-12 to 11-in-12: 1.2 roof pitch
  • 6-in-12 to 8-in-12: 1.1 roof pitch
  • 4-in-12 to 5-in-12: 1.05 roof pitch
  • 0-in-12 to 3-in-12: 1.0

In part two of this series, we’ll go over the final areas to calculate and how to merge your numbers together to get the final tabulation. For more on this, or to learn about any of our rain gutter or window screen services, speak to the staff at Wizard Rain Gutters today.