5-Inch vs. 6-Inch Gutters for Wichita Homes

The short answer

Most residential homes use 5-inch K-style gutters, and HomeGuide notes that homes with heavy rainfall or large roof areas may need 6-inch gutters, with a professional calculating the size from the roof's square footage, pitch and local rainfall intensity (HomeGuide, gutter installation cost). In practice, 6-inch gutters are worth considering on larger homes, steep roofs, long runs, roofs with valleys that funnel water into one corner, and anywhere 5-inch gutters overflow when clean.

What goes into sizing a gutter

• Drainage area. The amount of roof that drains into each run, not the size of the whole house. A big back roof plane may need more capacity than the front.
• Roof pitch. Steeper roofs catch more wind-driven rain and send water into the gutter faster, so sizing methods adjust the area upward for pitch.
• Rainfall intensity. Gutters are sized for short, intense downpours, not annual totals. Wichita's annual average is a little over 34 inches (Wikipedia: Wichita, Kansas (climate)), but what matters for gutters is how hard it rains during a summer thunderstorm. NOAA's Precipitation Frequency Data Server publishes local rainfall intensity estimates used for this kind of design (NOAA Precipitation Frequency Data Server (Atlas 14)).
• Valleys and dormers. Where two roof planes meet, water concentrates and hits the gutter hard.
• Downspout count and size. A gutter can only drain as fast as its outlets.

Downspouts: half the equation

Many overflow problems blamed on gutter size are really downspout problems. A 5-inch gutter is usually paired with 2x3-inch downspouts; a 6-inch gutter with 3x4-inch downspouts, which carry considerably more water and are less likely to clog with leaves and seeds. Adding a downspout to a long run, or upsizing outlets on a busy corner, can solve overflow without replacing the gutter. See downspouts and drainage.

Signs your gutters may be undersized

• Water sheets over the front of clean gutters in heavy rain.
• One corner, usually below a valley, overflows every storm.
• Erosion lines or splash marks under the eaves despite gutters.
• Downspouts run full and still cannot keep up.
• The house has a large, steep or complex roof with standard 5-inch gutters and few downspouts.

Before blaming size, rule out clogs, sags and a backward pitch. The guide why gutters overflow walks through the checks.

5-inch vs. 6-inch at a glance

Other size-related upgrades

• Valley splash guards keep water from shooting over the corner.
• Thicker material keeps larger gutters from flexing. See aluminum gutters.
• Stronger hangers at closer spacing for the extra weight of water and debris.
• Mixing sizes: some homes use 6-inch only on the busiest runs and 5-inch elsewhere, although matching profiles look more consistent.

Requesting an estimate

Describe where overflow happens and how the roof is laid out, and send photos of the problem corners during rain if you can. We'll call you back to talk it through.

A simple way to think about drainage area

Sizing methods start with the square footage of roof that drains into a run, measured in plan (as if looking down from above), then adjust for pitch. A ranch with a long, shallow back roof might send 600 to 800 square feet of roof to one gutter run, while a two-story house with a steep gable roof and a valley might send a similar area to one corner much faster. That is why one side of a house can overflow while the other is fine. Installers who measure each roof plane, rather than using one size for the whole house, tend to get sizing right.

Seven-inch and commercial gutters

Commercial buildings, churches, large shops and some very large homes use 7-inch or box gutters with 4x5-inch or larger downspouts. They are less common on houses but worth asking about for big metal-roofed shops and barns, where large roof planes shed a lot of water at once.

Sizing and gutter guards

Some guards reduce how much water a gutter can take in during intense rain, especially on steep roofs. If you plan to add guards, it is another reason to make sure the gutter and downspouts have capacity to spare. See gutter guards.

Do it once

Upsizing existing gutters usually means replacing them, since a 5-inch gutter cannot be enlarged. If your current gutters are in good condition and overflow only at a corner or two, start with downspouts and splash guards. If the gutters are old or damaged anyway, choosing the right size during replacement is the most cost-effective moment.

Questions to ask about sizing

• How did you size each run: by roof area, pitch, or a standard size for the house?
• Which corners or valleys will get extra capacity or splash guards?
• How many downspouts, what size, and where will they discharge?
• Will 6-inch gutters need different hangers or spacing?

For houses with complicated rooflines, it can help to ask for a simple sketch showing which roof areas drain to which downspouts. It makes the estimate easier to compare and shows whether the busiest corners have enough capacity.

Why size matters more in storm country

South-central Kansas gets much of its rain in short, heavy bursts during spring and summer thunderstorms rather than slow, steady rain. A gutter that handles a gentle shower easily may overflow in the first ten minutes of a downpour, which is exactly when water against the foundation does the most harm.

Photos of the problem corner taken during a heavy rain are the single most useful thing to have when sizing is in question.

What does it cost? See published national ranges for gutter sizes in the gutter cost guide. They are general industry estimates, not quotes.

Related guides

• Why Do My Gutters Overflow? 8 Causes and Fixes
• Where Should Gutters and Downspouts Be Placed?
• Can I Install Gutters Myself? What DIY Really Involves