Standard Gutter Downpipe Size

See photos below most residential gutters will measure approximately 5 inches across the top with the actual opening being approximately 4 5 inches.

Standard gutter downpipe size.

5 inch standard k style gutter shop 5 gutterbrush. This type of down spout is considered the standard downspout style in households and is used with a 5 k style guttering system. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed. The downspout and gutter sizing calculator is located on the tools cad and apps page of the smacna website.

Size downspouts to fit the gutter. Select 100 x 50 rectangular downpipe. Rainline gutters are available in two shapes and five sizes. 75mm 87mm 100mm and 120mm.

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. Doubling the number of downspouts halves the required capacity for each. The sizes available in this style are 3 4 5 and 6. 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.

There is no limit to downpipe size or eaves gutter size. Standard square downpipe size is 65mm. 100mm 125mm 150mm 190mm and rectangular 136mm. A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour.

The system offers good flow capacity when removing rainwater from your roof suitable for new builds house refurbishments conservatories and extensions read more. Use this handy guide to make sure your rain collection is up to the task during even the heaviest storm. You can choose a downpipe size and calculate the number required and the corresponding eaves gutter size. Standard round downpipe size is 68mm.

Note that a minimum gradient of 1 500 is preferred. It also comes in sizes 2 3 and 3 4. Measure your gutter across the top from the back where the gutter meets the home to the outer edge. Now architects engineers designers and contractors can easily and accurately size downspouts and gutters according to the specifications in smacna s architectural sheet metal manual 7th edition 2012.

The 68mm x 67 5 white branch is used to connect 2 neighbouring round downpipes at a 67 5 angle. From table 3 3 in as nzs 3500 3 the minimum size downpipes compatible with spouting of 6125mm 2 cross sectional area installed at a 1 500 gradient are 90mm diameter round or 100 x 50 rectangular. The code limit is 150mm for dp s and 26 800 sq mm for flat eaves gutters. The program will calculate the size and number of downpipes downspouts leaders required and the eaves gutter sizes for any roof.