Downspouts also come in.
How to size gutters.
Measure your gutter across the top from the back where the gutter meets the home to the outer edge.
Make sure the ladder extends at least three feet.
Gutters come in different sizes.
You ll also need to.
They ll cost more and probably require a custom order through a professional installer.
How do you do the math to figure out how large your gutters should be.
You have three options.
Each square inch of downspout cross section can drain 100 sq.
A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour.
Per ft and you can multiply the watershed by 1 4.
Adjusting for pitch and rainfall.
Gutters come in different sizes.
How to size gutters downspouts 1.
The standard is about inch per 10 feet.
Pitch your gutters by 1 8 in.
Size downspouts to fit the gutter.
Consider your drainage area.
Gutters typically come in 5 or 6 in 13 or 15 cm sizes and can be k style or half round place a sturdy 20 ft 6 1 m ladder on 1 side of your house so that you can reach the gutters.
Area and flow in table 1 4 are based on 1 in 25 mm of rainfall per hour.
Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed.
Increase the pitch of the gutter.
Place the torpedo level on the roof with the level body sitting perpendicular to the roof peak.
Increasing the pitch increases a gutter s.
Calculate your roof.
5 inch standard k style gutter shop 5 gutterbrush.
Spout drains 1 200 sq.
Measure the length and.
What size gutters do you need.
Divide these areas by the local rain fall rate in inches per hour to determine the actual roof area to be served by the gutter diameter.
How do you calculate gutter size.
Set up an extension ladder against one edge of your home s roof.
They can be 4 5 or 6 inches.
Multiply the drainage area by the roof pitch factor and rainfall intensity to find out the adjusted.
Find the width of the gutters.
From chart 1 2 it is determined that a 9 5 in 241 mm half round gutter should be used.
Carefully climb up the ladder and measure the width of the opening at the top of the gutters.
The steeper a roof s pitch the more windblown rain it can collect.
This determines the maximum watershed level gutters can serve between downspouts.
Ft and a 3 in.
See photos below most residential gutters will measure approximately 5 inches across the top with the actual opening being approximately 4 5 inches.
