Why Is My Home's Siding Rotting Near the Foundation?

Rot near the foundation usually comes from water that splashes off the ground during rain. When the soil slopes toward your home, runoff pools against the siding and soaks in. Over time, that trapped moisture lets fungi break down the wood fibers, turning the siding soft and crumbly.

Another common cause is clogged or short gutters. Water that spills over the edge runs straight down the wall and collects at the base. Splashback from hard rain also wets the lower boards repeatedly. In a humid continental climate, the combination of wet soil and warm air keeps the wood damp for long stretches, which invites rot.

Start by fixing the grading around your home. The soil should slope away from the foundation for at least 6 feet, so rain runs off instead of pooling. Add downspout extensions to carry gutter water at least 5 feet from the wall. Keep the area clear of leaves and debris that trap moisture.

If the siding is already wet, let it dry out before you paint or seal anything. Remove any rotted boards and replace them with new, pressure-treated lumber that resists decay. For extra protection, install a drip edge or a metal flashing at the bottom of the wall to keep water away.

Keep gutters and downspouts clear every season, especially before winter. In cold climates, ice dams can force water under the siding and down the wall. Trim shrubs and plants so they do not hold moisture against the house. Leave a small gap between the soil and the bottom of the siding.

Inspect the base of your home twice a year, after heavy rains and after snowmelt. Look for new stains, soft spots, or peeling paint. If you live in Detroit, watch for freeze-thaw cycles that can crack the foundation and let water seep in. Catching problems early saves you from bigger repairs later.