Living & Environment Products Div. helps people lead fuller lives.

Calculations of rain gutter drainage capacity

The drainage capacity of a rain gutter is determined by the following factors: the projected area of the roof; rain intensity/slope of eave trough; and size of eave trough and vertical downspout. Enter the required information below and click Calculate to calculate the drainage capacity of your rain gutters.

Configure Calculation

1. Calculate the projected roof area


2. Configure the rain intensity and slope of eave trough.


Note: Rain intensity of 100 mm/h or more is extremely rare (about once in five to six years).

3. Determine the type of eave trough and vertical downspout.

* Only pipe VP and VU pipe meeting JIS standard.
* We do not manufacture pipe VP or VU pipe.


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Living & Environment Products

Housing & Environmental Materials Department