For design purposes and aesthetics let s assume you have selected an 8 gutter.
Gutter and downspout dimensions.
Adding a 2 by 3 rectangular downspout for instance boosts your gutter s capacity by 600 square feet of drainage area.
Rainfall intensity is measured in inches per hour at a 5 minute interval.
Use the chart below to figure out how many extra downspouts you need.
The flexible design easily bends and holds its shape and can be extended from 25 in.
Use this downspout extension to divert water away from the foundation or connect to drainage pipe and catch basin to control drainage.
But more could be.
The size of the downspout should be constant through out its length.
How to figure the right downspout size.
The downspout size must suit.
Rectangular 2 by 3 inches 600 square feet 3 by 4 inches 1 200 square feet.
Downspouts should be constructed with conductor heads every 40 ft 12 2 m to admit air and prevent vacuum.
Most downspouts are rectangular but they can also be round or square.
See photos below most residential gutters will measure approximately 5 inches across the top with the actual opening being approximately 4 5 inches.
Round 3 inches 706 square feet 4 inches 1 255 square feet.
As with gutters a downspout s capacity must match or exceed the expected runoff.
Measure your gutter across the top from the back where the gutter meets the home to the outer edge.
Continuing with our example in the last step we know our gutter downspout system may be subject to as much as 1 880 gallons per minute.
The most common gutter sizes are 5 inches and 6 inches although 4 inches is available as well.
Practically speaking though a common gutter size is usually selected and downspout spacing is equal for most buildings.
The sizes available in this style are 3 4 5 and 6.
However too large a gutter downspout can look unattractive.
The gutter outlet capacity should suit the downspout capacity.
Round downspouts come in various sizes and colors and mostly used with half round gutters.
This type of down spout is considered the standard downspout style in households and is used with a 5 k style guttering system.
You should be able to.
5 inch standard k style gutter shop 5 gutterbrush.
Offset of more than 10 ft 3 0 m can affect drainage capacity.
Gutter downspout sizes are 3 to 6 inches.
The larger a gutter downspout the more water it can drain quickly.
Downspouts are commonly 2 x 3 inches and 3 x 4 inches in size or 3 or 4 inches in diameter.
