Seamless Gutter System Minnetonka Minnesota

Calculate the best size for your house

Gutters are essential to the longevity of most homes. Without gutters and downspouts leading rainwater away from the house, foundations become feedlots for mold that can sicken your family and rot your house. Once you’ve settled on a material, and a profile, you’ll need to pick a size. This procedure for sizing your gutter system is based on roof size, your area’s likely rainfall intensity, gutter volume and downspout size and frequency.

1. Calculate your roof’s watershed area — A roof’s watershed area isn’t obvious. Maximum rainfall is likely wind driven, so steep roofs may collect more water than flat roofs. To figure a roof’s watershed area, multiply its surface area by the appropriate factor on the table.

2. Find the maximum likely rainfall intensity — Residential gutters are often planned to handle the most intense five-minute burst of rain, measured in inches per hour, that’s likely to occur in a ten-year period. Find yours on the map.

This link will give you the yearly rain fall in your area. // (Courtesy of

3. Determine the gutter needed to drain your watershed — Divide your favored gutter’s 1-in.-per-hour watershed (see the chart below) by the five-minute rainfall intensity (from the map above). This determines the maximum watershed level gutters can serve between downspouts. Pitch your gutters by 1/8 in. per ft., and you can multiply the watershed by 1.4.

Each square inch of downspout cross section can drain 100 sq. ft. of watershed. So a 2-in. by 3-in. spout drains up to 600 sq. ft., and a 3-in. by 4-in. spout drains 1,200 sq. ft.

Going from one downspout to two doubles the watershed that a section of gutter can drain.

Sample house — An 8-in-12 pitch shed roof¬† is 40 ft. wide, and its rafter length is 20 ft. The roof’s area is 800 sq. ft. The pitch factor for an 8-in-12 pitch roof is 1.1; when multiplied by 800 sq. ft., that gives a watershed of 880 sq. ft. The theoretical 5,520-sq. ft. watershed drained by a 5-in. K-style gutter, divided by 6.6-in.-per-hr. rainfall intensity, shows a maximum watershed of 836 sq. ft. Close, but to be safe, the contractor should either pitch the gutter, use a larger gutter or add another downspout.

Never underestimate the power of your gutters. Sure, they may seem useless but, in reality, it is your gutters that keep the rest of your house from crumbling. When your gutters are blocked, cracked or damage, you may notice that the entire roofing system is faulty. You may also notice your roof collapsing right before your eyes.  If your gutters are not working properly, then you can expect additional problems down the road.

A Minnesota Gutter Installer will be happy to answer any questions you may have about installing a new Seamless Gutter System on your home.

COVID-19 Update

We are open and following all recommended state and national safety recommendations during this time. We can also operate 100% contact free from consultation to job completion if you prefer.
Thank you for your business, and we wish you and your family continued health and safety!
Tim Hanson
Owner, Minnesota Leafless Gutters

You have Successfully Subscribed!