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Gutter Sizing

Get recommended gutter size and downspout count based on roof drainage area per SMACNA standards.

Gutter Sizing

Get recommended gutter size and downspout count based on roof drainage area and rainfall intensity.

Horizontal projected area draining to this gutter run

Check your region: NOAA rainfall intensity maps or local building code

Gutter Size5in
Downspouts Needed1downspouts
Source: SMACNA Architectural Sheet Metal Manual. 5-inch gutters are standard residential; 6-inch for larger roofs or high-rainfall regions. Reduce downspout spacing to 20 ft maximum for best drainage.

For reference only. Verify with your local building code and a licensed professional before making decisions.

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