Protecting Your Home: Understanding Placement of Downspouts
Downspouts form a connection between the roof and the basement of your house. That connection is rainwater shed by the roof that infiltrates basement walls, causing a chronically wet basement. Water seepage into basements is a major problem that deteriorates basement structure and can make the interior basement space unusable for many purposes, as well as a source of mold contamination and other moisture-related issues. This is why placement of downspouts is so important. One inch of rainfall on a 1,000 square foot roof equals over 600 gallons draining through gutters and into downspouts. Homeowners may expend large amounts of money and time on attempts to seal basement walls against water seepage. Often, proper placement of downspouts is a more cost-effective method that achieves better results simply by reducing the volume of roof runoff soaking into the ground.
Here are some guidelines for placement of downspouts:
- As a general rule at least one downspout should be placed per every 40 linear feet of gutter. This ensures adequate drainage to prevent overflowing gutters during heavy rain. An overflowing gutter cascades onto the ground below, forcing water into the ground immediately adjacent to the foundation wall and exacerbating seepage into the basement.
- Downspouts should not discharge where water may pool close to the house and foundation. Paving stones or walkways that aren’t properly pitched away from the exterior wall can act like dams that cause water to back up next to the structure and greatly increase the amount of ground seepage and infiltration into the basement.
- If downspouts cannot be relocated to a position where water drains properly away from the house, downspout extensions should be installed. These should be long enough to move the discharge point of water a minimum of four feet away from the house.
- Where neither of the above options is doable, a downspout should be placed where it can be connected to an underground pipe that routes water far from the house into the yard or into the municipal storm sewer (if local laws permit.)