How to Control the Erosion Around a House Foundation…
Heavy rains can cause soil erosion in just a few hours.
Soil erosion around a house foundation is just as much a problem for homes on flat land as it is for homes on slopes. And even though your area might not get a lot of rain annually, if you live in California, for example, you could still get inundated. The “Pineapple Express” — a term for a specific meteorological band of moisture that flows inland from the Pacific — can dump an excessive amount of rain in just a few hours, eroding the soil away from your foundation in mere hours. Being prepared can help you control soil erosion.
Gutters and Downspouts
Add gutters and downspouts to the eaves of your roof to catch rain when it falls and direct it where you want it to go. Set downspouts so that they drain the water from the roof at least 5 feet from the house for homes built on sandy or compacted soil, or at least 10 feet away from the house on soils that expand. The gutters go on the long end of the house eaves, not on the gable ends.
One of the easiest ways to control erosion around a house foundation is by using landscaping or decorative measures that serve a dual purpose. Plant grass or another type of low-to-the-ground covers to keep the soil where you want it. Other options include landscape timbers, concrete pavers, liners, rocks or gravel. While bark looks nice against the foundation, it is not heavy enough to stay in place in a downpour.
French Drain It
Install a French drain system around the house foundation. When your foundation extends several feet beneath the soil’s surface, dig a trench, line it with gravel and place a special drain with perforations in it to pull the water away from the house. This works best for raised floor foundations with footings below ground level. Cover the drain with gravel, and then add soil over the gravel. Make certain the trench has a 3 percent to 5 percent downslope to it to allow the flow of water away from the foundation.
Repair the Grade
Assess the slope around the foundation. The soil should slope between 3 percent to 5 percent within 10 feet of the foundation. If it does not, add soil and a ground cover to keep it in place. If you cannot repair the grade, dig down and add a moisture barrier to the foundation, if possible. Otherwise, create a swale with a slight downslope to channel water away from the house. You can line the swale with concrete or rock. But the rock must be heavy enough so that it stays in place during those Pineapple Express downpours.
Monitor drainage during a storm. If you have a grated drainage system that moves water downslope, keep the drains free of leaves and debris. The same applies to a gutter and downspout system on your roof. If the gutters and downspouts become clogged with leaves, the water can flow in places you don’t want it to and cause erosion quickly in a downpour.