Roof gutters
 

Gutters and downspouts collect and carry away rainwater that would otherwise run off the roof, splash down and erode the soil and stain the siding. More important, gutters and downspouts form the first line of defense against a wet basement or crawl space: If you let water collect along the foundation, hydrostatic pressure will build, and water will eventually find its way inside the house.http://www.epdmcoatings.com/liquid-roof.html