Standard Rain Gutter Sizes

Downspout sizes must not exceed the bottom width of the gutter.

Standard rain gutter sizes.

Gutter downspout sizes are 3 to 6 inches. It also comes in sizes 2 3 and 3 4. Furthermore the standard norm for gutters among many in the rain carrying industry is to allow 1 square inch of outlet opening in the gutter for every 100 square feet of roof area being drained. A steep pitched roof can accelerate rainwater velocity.

5 inch standard k style gutter shop 5 gutterbrush. See photos below most residential gutters will measure approximately 5 inches across the top with the actual opening being approximately 4 5 inches. But houses with big steep roofs or those located in climates prone to heavy downpours may need wider gutters and extra downspouts to keep rainwater from overflowing. Those gutter machines also only form one rain gutter profile k style half round or box for example.

Five inch k style gutters or 6 inch half rounds the most common residential sizes are able to handle the rainfall on most houses in most parts of the country. Roof slope rainwater must not overrun the front edge of the gutter. Measure your gutter across the top from the back where the gutter meets the home to the outer edge. Most downspouts are rectangular but they can also be round or square.

The larger a gutter downspout the more water it can drain quickly. The second most common style of downspouts in urban homes is the rectangular downspout coming under a range of sizes such as 2 3 3 4 and 4 5. Most gutter installers portable gutter machines typically produce gutters in a 5 or 6 width and sometimes 7. This type of down spout is considered the standard downspout style in households and is used with a 5 k style guttering system.