Gutter Downspout Requirements

Place downspouts at least 20 feet apart but no more than 50 feet apart.

Gutter downspout requirements.

Come visit our selection of quality products. Allowance per square inch of downspout for 1 in hr 25. Gutters and downspouts need to be sized to accommodate anticipated water loads. Welcome to gutter supply your online reference for gutters gutter machines gutter guards and accessories.

A damaged section of gutter. Secure the downspout outlet to the gutter with four pop rivets or screws. 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. For example if you have 30 feet of guttering the calculation is 1 4 x 3 0 75 i e.

Screw a downspout elbow to the outlet tube protruding down from the gutter. Doubling the number of downspouts halves the required capacity for each. A high slope moves water more quickly and if gutters have trouble dealing with a lot of water in a short. From chart 1 2 it is determined that a 9 5 in 241 mm half round gutter should be used.

From table 1 3 it is found that a4 in 102 mm downspout is required. Adding a 2 by 3 rectangular downspout for instance boosts your gutter s capacity by 600 square feet of drainage area. This means the downspout end of the gutter should be set 3 4 of an inch lower than the other end. Allow 1 square inch of downspout cross section for every 100 square feet of roof area.

Wood rot behind gutters. Quite often you will see downspouts that are short and discharge onto the roof which is. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed. Plumbing codes typically use the vertically projected roof.

Hold another elbow against the house and cut a piece of downspout to fit between the two elbows. Use needlenosed pliers to slightly crimp the elbow to fit into the downspout as shown. The number of downspouts will depend on the cross section dimension of the downspout material. As a general rule gutter slope is set at 1 4 inch per 10 feet of guttering.

Area for drainage design and they often use a square foot. Use the chart below to figure out how many extra downspouts you need. Mm hr rainfall that varies with diameter for example 3. Downspout empties onto the roof.

The more roof surface above the gutters the more rainwater will be caught and funneled down into those. I have seen several downspouts dented or bent due to mechanical damage. Lots of times you will find that downspouts are missing from the gutter system. Gutters come in many sizes.

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