What Is A Downspout And Its Function

Wondering what that long, vertical pipe is that carries rainwater from your home's gutters down to the ground? That handy fixture is called a downspout, and it serves the vital roles of protecting your home from water damage while also redirecting unsightly pooling away from high-traffic areas. But what exactly is a downspout, what does it do, and why is proper installation and maintenance so important?

We'll also overview proper sizing, materials, placement and maintenance to keep your downspouts in top working order.

Defining The Key Purpose Of A Downspout

Known variably as a leader, rainspout or simply spout, a downspout is the vertical pipe that transports rainwater from a building's gutter system down to the ground. It serves as the critical drainage conduit that protects structures from possible water damage due to accumulation and runoff.

Without a properly functioning downspout, gutters have no efficient way to redirect captured water away from a building. This exponentially increases the risk of moisture damage, mold, flooded basements and cracked foundations over time from excessive exposure.

Preventing Damage By Redirecting Water

The core purpose of any downspout is to carry rainwater from a home or building's gutters down and safely away from its foundation. By redirecting runoff through downspouts instead of letting it overflow gutters, the risk of moisture damage to surrounding landscapes, basements and structures is greatly mitigated.

In most cases, downspouts empty rainfall out at least 5 feet from a home's foundation. This prevents saturation and flooding closest to the structure. Proper downspout drainage systems are angled and directed in a way so that discharged water flows away from a home through landscaping or other means.

Enhancing Curb Appeal By Managing Rain Runoff

In addition to their functional purpose, downspouts also help minimize standing puddles that can accumulate around homes after storms. By quickly transporting rooftop runoff down and away from high-traffic spaces, downspouts enhance aesthetic curb appeal.

Their vertical design bleeds rainfall away before large, unsightly puddles can form on patios, walkways, driveways and landscaped areas. Downspouts discharge water into drain pipes, French drains, rain gardens, dry creek beds and other means to conceal unwanted pooling.

Where Are Downspouts Typically Installed?

Downspouts are always connected to a building's gutter system, positioned vertically alongside exterior walls near the roofline. This placement allows gravity to easily and efficiently pull captured rainwater from gutters directly down pipes to the ground below.

Connected To Gutters To Receive Water Flow

Gutters rest on the edge of sloped rooflines with a slight pitch, catching rain runoff from shingles. At the roof edge, gutters then angle downward slightly to feed water to their connected downspouts. So downspouts serve as the drainage endpoint for gutters.

In most installations, downspouts connect to gutters via an outlet tube that fits into a hole cut near the bottom of gutters. The angled gutter then gravity-feeds its captured water into the top of this downspout outlet. From there, downspouts carry the runoff the rest of the descent.

Positioned Along Exterior Walls For Straight Transport

For efficient vertical water transport, downspouts run directly down alongside exterior walls rather than out across open space. This allows them to connect gutters to ground level using the shortest possible straight descent for water flow.

Downspouts adjacent to walls also tend to be more protected from damage. And they're less visible than standalone downspouts, enhancing aesthetics. For these reasons, downspouts around a structure's perimeter are the most common installation strategy.

Angled Away From Foundations

While downspouts need to descend directly alongside walls beneath associated gutters above, most then angle their discharge away from foundations once nearer to ground level.

Redirecting water flow a safe distance from a home's foundation prevents flooding and moisture damage risks. So most downspouts utilize elbow joints during final descent to angle discharged water away from structures through drain pipes, French drains or landscaping.

Materials Used To Manufacture Downspouts

Downspouts comprise a simple vertical tube that transports water downward. So most any hollow building material can be fabricated into functional downspouts. But the most common options include:

• Aluminum downspouts - Durable, affordable, low maintenance option for most climates.
• Copper downspouts - Gorgeous, longer lasting though costs more upfront.
• Vinyl downspouts - Affordable, low maintenance though less durable long-term.
• Galvanized steel downspouts - Durable and cheaper than copper but requires more maintenance.

Aluminum

Painted aluminum is likely the most widespread downspout material used today. It offers an ideal blend of durability, affordability and low maintenance.

Aluminum downspouts hold up well to weathering, denting and other damage risks. They also tend to cost less upfront than premium materials like copper. And painted aluminum requires very little upkeep beyond occasional aesthetic touch-ups.

Copper

Natural copper downspouts are beloved for their gorgeous, upscale appearance and exceptional durability. Pure copper weathers elegantly to a natural patina over time rather than requiring paint.

Copper resists corrosion far longer than other metals, often lasting 50-100 years. This extensive lifespan offsets copper's considerable upfront expense for a sound long-term investment. But material and installation costs are notably higher than basic aluminum.

Vinyl

For a very affordable and low maintenance downspout option, plastic vinyl is readily available. Vinyl won't corrode, dent or require painting. But it tends to become brittle and crack more quickly than metal in extreme weather.

Vinyl downspouts are best suited to mild, temperate climates rather than extreme cold or heat. Durability is lower, so vinyl doesn't always justify its lower price over time compared to aluminum or copper.

Galvanized Steel

Galvanized steel downspouts are essentially steel coated in zinc to resist corrosion. This makes galvanized steel more durable and longer-lasting than basic steel at a moderate price point. But it still requires occasional touch-up painting as the zinc coating degrades.

In terms of durability per dollar, galvanized steel downspouts are comparable to painted aluminum. Both tend to outlast vinyl while carrying a more budget-friendly price tag than pure copper. So galvanized steel makes an appealing middle-ground choice for many homeowners.

Sizing Downspouts Properly

It's not a one-size-fits-all scenario when it comes to choosing and installing correctly sized downspouts. To promote optimal drainage efficiency, you need to factor in variables like regional rainfall rates and collection capacity from the attached gutter system.

Consider Your Roof Size And Average Rainfall

The larger your overall roofline area, the more rainwater runoff it will generate during storms. Similarly, areas prone to frequent heavy rainfalls should err toward oversized downspouts to manage potential overflow.

A good rule of thumb is allotting 1 square inch of downspout capacity for every 100 square foot of roofline area that will drain into it. So for a typical 1500 square foot ranch home, each connected downspout should offer around 15 square inches of transport space.

Most gutter and downspout manufacturers provide vital technical specs like water flow capacity per linear foot. This measures how much rainfall their models can transport straight down without overflow risk.