How to Choose the Right Gutter Size
To maximize the efficiency of your gutters, you need the correct size. Gutters come in a variety of shapes and sizes, with 5-inch K-style gutters and 6-inch half-round gutters being the most popular choices. However, if your home is located in an area with heavy rainfall, or if your roof is extremely steep, you might need a larger gutter to prevent rainwater overflow.
To ensure you choose the right gutter size for your home or business, you need to consider three factors: your roof size, your roof’s pitch (also known as the steepness angle), and local rainfall intensity.
Find Your Drainage Area
The first step is to determine how much water your gutters will need to contain. The larger your roof, the more water will flow down to your gutters. Your roof's total surface is called the drainage area, which can be determined by finding the surface areas of each facet of your roof. Find the area of each side by multiplying its length by its width. This is a simple process for a standard two-gabled roof, but it can be more complicated if your roof has multiple facets.
Determine Your Roof Pitch
Next, you need to determine your roof pitch, which reflects the steepness of your roof. Water collects quickly in gutters with steep roofs, since it slides down the roof at high speeds. Gutters with steep roofs can overflow rapidly if they’re not large enough to contain the spillage.
You will need a level and a measuring tape to calculate your roof pitch. Begin by holding the level straight against your roof's slope and then measure the distance between the middle of the level to your roof. Your roof pitch factor depends on this distance. Below is a table showing roof pitch factors for different distances.
Distance Roof Pitch Factor
3 inches or less 1.0
4 inches 1.05
6 inches 1.1
9 inches 1.2
12+ inches 1.3
Consider Your Local Maximum Rainfall Intensity
Your gutters will have to face the elements, so make sure that you choose a gutter that can withstand your local weather conditions. If your area has intense downpours, you need a larger gutter system to accommodate larger quantities of water. Rainfall intensity is measured in inches of water per hour. The United States Weather Bureau provides regular metrics for regional maximum rainfall intensity around the country.
Calculate Your Gutter Size
Now that you have all the necessary data, you can calculate your adjusted square footage. Your adjusted square footage will help you determine your ideal gutter size. Multiply your drainage area by your roof pitch factor and maximum rainfall intensity to find your adjusted square footage.
Use the below table to determine the recommended gutter size and style for your home, based on your adjusted square footage.
Five-inch 5,520 square feet 2,500 square feet
Six-inch 7,960 square feet 3,840 square feet
Choose the Gutter Installation Austin, Texas Homeowners Can Trust
While you can perform these measurements yourself, you need experienced professionals to get the best results. At Austin Gutter King, we have almost twenty years of expertise in helping our clients find the gutters they need. When it comes to gutter installation, Austin, Texas residents know they can rely on Austin Gutter King. Contact us today for a free consultation to help choose the right gutter size for you!