At TheRemodelers.org we don't sell anything. Instead we provide information that helps our community make decisions regarding home improvement services and projects. Click below for recommended licensed professionals that provide free no obligation quotes.
Understanding Gutter Downspouts
Tom Silva, This Old House
Apr 06, 2026
Understanding Gutter Downspouts (Types, Installation, and Drainage Tips)
Downspouts are a critical part of your gutter system.
They move water from the gutters down to the ground and away from your home’s foundation.
Why Downspouts Matter
Gutters collect water, but downspouts are what actually carry it away.
Without proper downspout design, water can pool near your foundation and cause serious damage over time.
Gutter Outlet (Drop Outlet)
The outlet is the connection point where water leaves the gutter and enters the downspout.
It can be built into the gutter or added separately by cutting a hole and installing a connector.
A-Style Downspout
An A-style downspout is designed to sit flat against the wall.
It has a wider side and a narrower side, allowing sections to connect properly.
It’s important to install it in the correct direction to prevent leaks at the seams.
B-Style Downspout
A B-style downspout is rotated 90 degrees compared to an A-style.
This allows you to change the direction of the water flow depending on the layout of your home.
Elbows and Direction Changes
Elbows are used to guide the downspout around overhangs, siding, and other obstacles.
Most installations require at least one or two elbows to properly align the downspout with the wall.
Handling Roof Overhangs
Because most homes have roof overhangs, downspouts rarely run straight down from the gutter.
A short extension piece is often used between elbows to bridge the gap from the gutter to the wall.
Downspout Diverter
A diverter is attached at the bottom of the downspout to direct water away from the house.
It helps move water 2 to 4 feet away from the foundation, which is critical for preventing damage.
Many diverters can fold up for easy lawn maintenance.
Why Water Must Be Moved Away
Water sitting near your foundation can lead to serious problems.
In colder climates, it can freeze and expand, damaging the foundation.
It can also lead to basement leaks, soil erosion, and structural issues.
Advanced Drainage Options
In more complex situations, longer extensions or piping systems can be used.
These can route water around obstacles like fences or landscaping and move it further away from the home.
Final Thoughts
A properly designed downspout system ensures that water flows safely away from your home.
Choosing the right style, direction, and extension can help prevent costly damage and improve long-term performance.
FAQ: Gutter Downspouts
What is the purpose of a downspout?
A downspout carries water from the gutter down to the ground and away from your home.
What is the difference between A-style and B-style downspouts?
A-style runs flat against the wall, while B-style is rotated to change the direction of water flow.
How far should water be directed away from the house?
Water should be directed at least 3 to 4 feet away from the foundation.
Do I need elbows on my downspout?
Yes. Most homes require elbows to navigate roof overhangs and properly align the downspout.
What happens if water is not directed away from the foundation?
It can lead to foundation damage, basement leaks, soil erosion, and other costly problems.