Q&A: Should I Add Another Downspout to My Gutters?

We frequently hear from homeowners seeking answers to repair and maintenance problems. Many of these questions and answers are compiled in our Home Improvement Library. Here is a recent question.

Question

I have a 41 foot span of guttering across the back of my villa that has only one down spout. The gutters overflow during heavy rain storms. The down spout is 2×3 inch. Do you think the solution is adding another down spout or replacing the 2×3” with a 3×4”, or both? Also do you have any experience with gutter cover products sold at the hardware stores?

Answer

You are correct about wanting another downspout, because a house does need one downspout per 40’ span for proper drainage. At Mosby Building Arts, we install 6” gutters with 3×4” downspouts because we find very few instances of gutters that work properly for the long haul with a 2×3” downspout. Please keep in mind that when enlarging the downspout you will also need to enlarge the hole in the bottom of the gutter, as well. And adding the second down spout will require adjusting or re-sloping the gutter. Currently, the whole span of gutter is likely sloping toward the existing single down spout. With an additional downspout, they will need to be adjusted so that the high point of the gutter is in the middle of the 41’ span, sloping downhill in both directions toward both down spouts. We also recommend using pop rivets rather than screws so less debris catches inside the system causing flow restrictions. 5” gutters typically get the 2×3” downspout, so be aware that if you add 3×4” downspouts to 5” gutters, it will look very odd. Since work must be done to add your additional, larger downspout, now would be the best time to switch out to 6” gutters, as well. To protect your foundation and basement, please make sure to properly drain the down spouts a minimum of 10 feet away from the house, or pipe the water underground. If you choose the underground method, use only smooth-walled PVC pipe. Please avoid the corrugated black drain pipes as they can create unnecessary blockages. As to gutter cover products, we recommend and use the Leafguard Gutters. The one-piece system protects the roof material and the roof warranty because it does not connect or jamb under the shingles which sometimes causes roof leak problems. We are not fans of gutter covers that are inserted into existing gutters. Many of the blockage problems St. Louis homes experience can be taken care of with 6” gutters with the proper number of 3×4” downspouts. But if a retro-fit of existing gutters with covers is the only option, we prefer Shur Flo, because it’s an aluminum tray, which gives far better performance than plastic or galvanized steel. Please be aware that this method of covering gutters can create a whole new set of drainage and maintenance issues, which is why we prefer an all-in-one, integrated system. For help with your gutter system, or for any water and moisture repair issues in your home, we’re here to help. In the Metro St. Louis area, please call the Mosby Building Arts office at 314.909.1800 or contact us here.

Why Work with Mosby Building Arts?

If efficiency, knowledge and quality craftsmanship are of the utmost importance, then Mosby is the partner for you. We are a design build firm that handles every aspect of your remodeling project from beginning to end. All team members needed to complete your project (designers, architects and production crews) are under one roof to provide time and monetary efficiencies, quality control, and seamless communication throughout.

Exterior Home Remodeling

Whether you are considering a new roof, replacement windows, or increasing curb appeal with a front door, understanding the return on investment is important. Homeowners often ask us if a project makes financial sense, or if it will increase the resale value of their home.

Learn more about exterior home remodeling here.

Outdoor Living Space Remodeling

Metro St. Louis weather lets you live outdoors for more than half the year. Mosby designs and builds the places for you to enjoy being outside. Make the most of your yards with outdoor living remodeling projects like decks, patio, pools, water features, outdoor kitchens, pergolas, gazebos, pavilions, porches, sunrooms, screen porches and more. All outdoor projects are designed with water management in mind to assure durability, covered by a 10-year workmanship warranty.

Learn more about outdoor living space remodeling here.

Home Remodeling Peace of Mind

There’s no need to deal with multiple companies, or the frustration of the left hand unaware of what the right hand is doing. Mosby takes the guesswork out of home remodeling by planning the work and working the plan. You will know the scope of work and price before the first hammer swings. And the work will be done with a commitment to excellence and your happiness. All of Mosby’s remodeling work is backed by our 10-year workmanship warranty.