Gutter Downspout Requirements

I have seen several downspouts dented or bent due to mechanical damage.

Gutter downspout requirements. As a general rule gutter slope is set at 1 4 inch per 10 feet of guttering. Hold another elbow against the house and cut a piece of downspout to fit between the two elbows. Size downspouts to fit the gutter. From table 1 3 it is found that a4 in 102 mm downspout is required.

Quite often you will see downspouts that are short and discharge onto the roof which is. Adding a 2 by 3 rectangular downspout for instance boosts your gutter s capacity by 600 square feet of drainage area. Use the chart below to figure out how many extra downspouts you need. Welcome to gutter supply your online reference for gutters gutter machines gutter guards and accessories.

Place downspouts at least 20 feet apart but no more than 50 feet apart. Are sized in relation to rainfall on this basis. Use needlenosed pliers to slightly crimp the elbow to fit into the downspout as shown. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed.

A high slope moves water more quickly and if gutters have trouble dealing with a lot of water in a short. Downspout empties onto the roof. Lots of times you will find that downspouts are missing from the gutter system. Come visit our selection of quality products.

Allow 1 square inch of downspout cross section for every 100 square feet of roof area. Mm hr rainfall that varies with diameter for example 3. Plumbing codes typically use the vertically projected roof. Area for drainage design and they often use a square foot.

As with gutters a downspout s capacity must match or exceed the expected runoff. Allowance per square inch of downspout for 1 in hr 25. This means the downspout end of the gutter should be set 3 4 of an inch lower than the other end. For example if you have 30 feet of guttering the calculation is 1 4 x 3 0 75 i e.

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 more roof surface above the gutters the more rainwater will be caught and funneled down into those. Screw a downspout elbow to the outlet tube protruding down from the gutter. 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.

Wood rot behind gutters. A damaged section of gutter. Secure the downspout outlet to the gutter with four pop rivets or screws. Doubling the number of downspouts halves the required capacity for each.

Gutters and downspouts need to be sized to accommodate anticipated water loads.