A Look at Downspout Elbow Differences: A vs. B

Gutter systems contain multiple parts and each one plays a specific role in directing water from the roof to the ground. As a professional installer, you understand that a gutter system may be more complicated than it appears to your clients.

In order to set your homeowner clients’ minds at ease, we’ve broken down the basics into simple terms you can share with them. This article will focus on the different downspout elbows available and which should be used in any given situation.

What Are Downspout Elbows?

One way to describe downspout elbows to homeowners is by explaining how they connect the main gutter system on the eave of their home to the downspout attached to the wall. The downspout directs the water to a final elbow at its base, guiding the water away from the home at the ground level. Elbows are manufactured in three shapes: rectangular, round and square.

Most of your residential applications will use rectangular elbows and downspouts. While they are available in many sizes, 2” x 3” and 3” x 4” are the most popular options. The elbows are available in either “A” or “B” shape and are configured in various angles:

  • 30-degrees

  • 45-degrees

  • 75-degrees

  • 90-degrees

The 75-degree elbow is the most common choice for most areas of the home, but 90-degree elbows are a good choice if you encounter a tight area that needs a sharper bend.

A-Elbow vs. B-Elbow

As you know, whether you use an A- or B-elbow will depend on how you want to connect the gutter to the main house and which direction you want the water to flow at the discharge point. There are numerous ways to direct the water once it leaves the gutter, but let’s consider a standard configuration for the purpose of demonstration.


A style Elbow

When explaining this to a homeowner, you can start by explaining how an A-style elbow is wider than it is tall. If you are looking at the downspout, an A-elbow discharges directly at you. In a regular application, the A-elbow would drop from the gutter and return back to the wall with the wide side lying against the building and connecting to the downspout. When used at the base of the downspout, an A-elbow channels the water directly away from the building.


B style Elbow

B-style is taller than it is wide. If you are looking at the downspout, the B-elbow turns to the right or left. This elbow is designed for use at the top and bottom of the downspout and is used at the gutter to run the downspout alongside the corner of the building rather than against the wall. As with the A-elbow, the flat side is attached to the home.

The Elbows Can Be Mixed in the Same Downspout Leg

Many homeowners may not realize that using one style to connect the gutter at the top does not mean you must use the same style at the bottom. You can use an A-style to connect the gutter to the home and a B-style at the end of the downspout. The choice of which style to use depends on which direction you want the water to flow away from the home. Be sure to consider ground elevation when choosing, to ensure the water continues to flow away from the foundation when leaving the downspout elbow.

How Are Elbows Attached to the Gutter and Downspout?

As you know, elbows are attached to the downspout with screws or pop rivets. At the gutter, the elbow is attached to a piece called the drop. Some systems have the drop built-in to a small piece that is attached at the end of the run. Your company may prefer to install your own drops and cut or punch an opening in the gutter at the best location for specific purposes.

What Size Gutter System Do I Need?

When homeowners ask this question, you can explain that sizing a rainware gutter system is easy using some simple guidelines. If their region receives just average annual rainfall, then a 2”x3” downspout system will be adequate for a roof with 800 to 1,000 square feet of surface area. If their roof area is 1,600 to 2,000 square feet, then a 3” x 4” system is recommended.

Alsco® Rainware Gutter System

Downspout Elbow A vs B: What Are The Main Differences?

The Alsco Rainware Gutter System carries a wide variety of accessories for almost every gutter installation — including A- and B-elbows. Our gutter system is made from low-maintenance, high-quality aluminum that is coated with our proprietary Gutter Tough Coating, which reduces the scratches and scuff marks that are associated with cheap, thin aluminum gutter systems. Our system also offers additional features and benefits:

  • Improved drainage

  • Reduced leakage and moisture problems

  • Wide variety of colors

  • Easy cleaning and maintenance

  • Industry-leading warranty for customers’ peace of mind

Alsco Metals Carries Gutter, Siding, Coil Stock and More

Alsco Metals has been manufacturing aluminum products for siding, roofing, gutters and accessories since 1947. We manufacture most of our products in our own state-of-the-art facility, allowing us to make sure that every foot of metal rolling off the presses is inspected and ready to be installed. That is why we confidently offer a limited lifetime warranty on our products.

Contact us today to speak with one of our customer service professionals who can direct you to the best Alsco product for your project.