Warning: one thing you skip this fall could flood your basement and crack your foundationEvery fall, millions of American homeowners walk right past a job that takes one afternoon and skip it for another year. If your house has a basement or a crawlspace, this is one of the most expensive mistakes you can make this season. It spills over, runs down the outside walls, and lands right at the base of your foundation. When leaves, pine needles, and roof grit pile up inside them through fall, they turn into a wet dam. A perfectly clean gutter still fails if the water it delivers dumps out six inches (15 cm) from your foundation.