Gutter Downspout Requirements

The more roof surface above the gutters the more rainwater will be caught and funneled down into those.

Gutter downspout requirements.

From chart 1 2 it is determined that a 9 5 in 241 mm half round gutter should be used. Allow 1 square inch of downspout cross section for every 100 square feet of roof area. Area for drainage design and they often use a square foot. Doubling the number of downspouts halves the required capacity for each.

A damaged section of gutter. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed. Come visit our selection of quality products. Hold another elbow against the house and cut a piece of downspout to fit between the two elbows.

As a general rule gutter slope is set at 1 4 inch per 10 feet of guttering. Size downspouts to fit the gutter. Plumbing codes typically use the vertically projected roof. Welcome to gutter supply your online reference for gutters gutter machines gutter guards and accessories.

Mm hr rainfall that varies with diameter for example 3. As with gutters a downspout s capacity must match or exceed the expected runoff. Adding a 2 by 3 rectangular downspout for instance boosts your gutter s capacity by 600 square feet of drainage area. Divide 1600 sq ft 149 sq m by 160 sq ft sq in 2 3 sq m 100 sq mm to determine that each downspout should have a minimum area of 10 sq in 6470 sq mm.

Quite often you will see downspouts that are short and discharge onto the roof which is. Use needlenosed pliers to slightly crimp the elbow to fit into the downspout as shown. Gutters and downspouts need to be sized to accommodate anticipated water loads. This means the downspout end of the gutter should be set 3 4 of an inch lower than the other end.

Screw a downspout elbow to the outlet tube protruding down from the gutter. Secure the downspout outlet to the gutter with four pop rivets or screws. The number of downspouts will depend on the cross section dimension of the downspout material. Gutters come in many sizes.

Allowance per square inch of downspout for 1 in hr 25. Are sized in relation to rainfall on this basis. A high slope moves water more quickly and if gutters have trouble dealing with a lot of water in a short. Place downspouts at least 20 feet apart but no more than 50 feet apart.

Lots of times you will find that downspouts are missing from the gutter system. From table 1 3 it is found that a4 in 102 mm downspout is required. I have seen several downspouts dented or bent due to mechanical damage. Wood rot behind gutters.

A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour.