Roofs are big, easy investments. Your home needs one roof. But with gutters how many downspouts do you need? Should you just have your gutter installer copy what you already have, even if you occasionally get overflowing gutters? Or should you hire hydraulic engineers and rocket scientists? Is there a middle ground?
What Downspouts Do
Most roofers will tell you, downspouts are the last part of your roofing system. Yup; gutters and downspouts catch all the runoff water from your Des Moines-area home’s roof and usher it out into your yard or into French drains. As such, they have to handle all the water your roof sheds during a typical rainshower.
A roofers’ rule of thumb is that every square foot of roof collects around 0.6 gallons per inch of rain, so:
- A typical residential roof is around 3,000 square feet
- Des Moines gets an average of 36 inches of rain a year, according to Best Places
- Your home’s roof sheds around 64,800 gallons of water a year or 5,400 gallons a month
- One foot of K-style, 5-inch gutter holds 1.2 gallons of water; 6-inch holds 2 gallons
- A 40-foot run of K-style, 5-inch gutter holds 48 gallons of water
- A 25-foot run of K-style, 5-inch gutter holds 30 gallons of water
Even a brief rainshower yields enormous water loads on your home’s gutter system. Your downspouts must be capable of handling the flow.
With downspouts strategically located every 25 to 35 feet, you can ensure your home’s gutters will not overflow. Overflowing gutters lead to all sorts of problems:
- Ruined landscaping
- Drowned plants
- Weakened foundations
- Rotten fascia trim
While most downspouts appear at the outside corners of houses, they can also be used to interrupt long gutter runs, fitted into an inside corner, or be run down a sloping retaining wall into the garden.
By providing ample downspout capacity, not even the hardest downpour can overload your gutters.
How Do You Know?
You may be the Master of the House, but nobody expects you to master all aspects of home ownership. Talk to your gutter installation service about the optimal downspout location and number. Many factors affect this:
- Roof pitch (angle)
- Gutter size
- Roofing material
Contact us today at VanWeelden Co. We can help you preserve and protect your Des Moines-area home with beautiful, practical new gutters and downspouts.