Downspouts are an important part of the gutter system. They are designed to direct water from the roof to the ground where it can be safely deposited away from your home’s exterior. Downspout elbows determine the direction of the flow of rainwater from the bottom of the downpipes. If you plan to DIY a gutter installation, have a professional contractor install them for you, or just want to know how downspouts work, here is what you need to know about downspout elbows.
Material and Colour
Just like seamless aluminum gutters and downpipes, downspout elbows are made from a variety of materials including aluminum, copper, and vinyl. It might be obvious to some but not to others, the elbows should match the material and color of the gutters – aluminum elbows for aluminum gutters and downspouts.
Downspout Elbow Types and Sizes
Downspouts should be flush against your home exterior. Downspout elbows allow you to position downpipes as close to the house as possible.
Types
The two main types of elbows are A and B. If the exit or bottom of the downspout faces directly toward you, it is an “A” elbow. When you’re holding the elbow with the flat pipe part facing you and the elbow is turned to the side, that is a “B” elbow. The differentiation between the two is an important factor regarding where you want the water to flow. For example, if the water will spill out onto the driveway, use a “B” elbow to empty the downspout into a flowerbed. When there is earth, gravel, mulch, or grass directly beneath the downspout install an “A” elbow.
Sizes
A standard 5 inch gutter system typically has a 2 x 3 downspout. In locales with a light to medium annual rainfall or 800 to 1,000 square feet of roof area, standard 5 inch gutters will be able to handle the amount of annual rainfall in the region.
For roofs that are 1,000 up to a maximum of 2,000 square feet or in geographic locations where the annual amount of rain is high, install a six inch gutter system with 3 x 4 inch downpipes and downspout elbows.
If you have a half-round gutter system or prefer round downspouts, the size of the corresponding gutter elbows will be a bit different. For standard 5-inch gutters, use 3” round downspout elbows. The corresponding downspout for a 6-inch gutter system is the 4” inch round. Round downspouts, both 3” and 4”, typically handle 20% more rainwater than their square counterparts. Round downspout elbows don’t come in “A” or “B” types – both round sizes have a general 70° bend.
What’s Your Angle?
The degree or bend of the elbow determines how the water flows through the downspouts. Different angles can provide specific downspout installation solutions.
30 Degree Bend
The smallest bend available in gutter elbows, a 30° angle provides a gentle slope for short distances between fascia and an exterior wall.
45 Degree Bend
Typically used on the upper parts of the downpipes, 45 degree gutter elbows provide enough of an angle to increase the velocity of water. This can help reduce the possibility of clogs forming around a gutter outlet where the downspout connects to the gutter system.
75 Degree Bend
The most common angle for downspout elbows for residential gutter systems is 75°. This sharp turn is capable of preventing clogs and ensuring the unimpeded flow of water. It is generally installed at the bottom of a downspout.
90 Degree Bend
Not typically found in hardware or big box stores, a 90° downspout elbow is used for specific applications. They are good for tight turns, going around corners, and depositing runoff further away from the foundation.
