For a lot of homes in the Chicago area, we recommend 6 inch gutters over 5 inch gutters. A 6 inch gutter can handle about 50% more water, and it drains into a bigger downspout.
A 5 inch gutter is enough for a small house with a roof that is not steep. Four things decide which size you need: roof size, roof pitch, rainfall and the look you want.
Our team installs 6 inch oversized gutters as our default. We fit 5 inch gutters too, when they suit the house.
What is the difference between 5 inch and 6 inch gutters?
Both sizes are K style gutters. K style is the most popular gutter shape on homes in North America. Most houses get either the 5 inch or the 6 inch size.
The 6 inch gutter is one inch bigger. It handles about 50% more water than a 5 inch gutter.
As the picture above shows, that inch makes a big difference. The two sizes also use different downspouts.
A 6 inch gutter drains into a 3×4 inch downspout. A 5 inch gutter drains into a 2×3 inch downspout, which has a smaller opening. Our guide to downspout size shows how to check the pipes on your own house.
What size gutters do I need?
Look at four things on your house. These are the 4 key differences that point you to a 5 inch or a 6 inch gutter.
Size of your roof planes
The bigger the roof, the more water goes into the gutter. A plane is one flat area of the roof with four edges, often one side of a gable or hip roof.
A plane of about 600 to 800 square feet can drain into a 5 inch gutter. At 1,400 square feet or more, we recommend 6 inch gutters, because about twice as much water comes off that roof.
Check the shingle edge too. If a roofer left the shingles more than 1.5 inches past the roof edge, water can shoot over the gutter in a hard rain. In that case we also recommend a 6 inch gutter.
Roof pitch
Pitch is how steep your roof is. A steeper roof sends water into the gutter faster.
The gutter has to take that water and move it to the downspouts, away from your home. A steep roof may need 6 inch gutters, even when its planes are only 600 to 800 square feet.
Rainfall in your area
The more rain your area gets, the more water your gutters have to move. A house in a dry place can do fine with 5 inch gutters.
Chicago is not a dry place. Here we recommend 6 inch gutters for a lot of homes.
Look and style
The width of your fascia board changes how the gutter looks. A wide fascia makes the gutter look smaller.
A 1×6 fascia usually gets a 5 inch gutter. On a 1×8 or 1×10 fascia, you need a 6 inch gutter to look in proportion.
New gutters cannot go onto soft wood. If the board behind your old gutters is soft, we replace the soffit and fascia as one job with the gutters.
6 inch gutters: pros and cons
A 6 inch gutter can handle about 50% more water than a 5 inch gutter. It also has a bigger outlet and a bigger downspout, so it is less likely to clog.
That makes 6 inch gutters the better fit for a big roof, a steep roof or a hard Chicago storm. The one drawback is the look, because a 6 inch gutter can look too big on a narrow 1×6 fascia.
5 inch gutters: pros and cons
A 5 inch gutter looks in proportion on a 1×6 fascia and on a smaller house. It is enough for a roof plane of about 600 to 800 square feet with a gentle pitch.
On a big or steep roof, a 5 inch gutter can spill over in a hard rain. Its 2×3 inch downspout also has a smaller opening, so it clogs sooner.
What are the most common gutter sizes?
5 inch and 6 inch are the two most common gutter sizes on homes. You may see smaller gutters on some houses too, and our post on 4 inch gutters answers that question.
Which gutter size do we install?
Our default is 6 inch oversized gutters, and we also install 5 inch gutters. When you are ready to price the job, this is the seamless gutter installation we fit on Chicago homes.
Each gutter is .032 inch aluminum, hung on QuickScrew hangers set every 24 inches. We seal the joints with GeoCel and add gutter apron flashing on every install. Every system comes with a lifetime warranty on materials and workmanship.
Whichever size you choose, check the materials and parts your contractor uses. Our guide to a good seamless gutter system lists what to look for.
Not sure about seamless yet? Read about the benefits of a seamless gutter system first. Then call us at (866) 488-7776 or get a free estimate, and we will help you pick the right size for your roof.
