Erosion / washout Erosion, or washout, is the removal of soil or base material by flowing water. Loss of support beneath pavement can lead to settlement and cracking.
Water from poor drainage, leaking utilities, or heavy rainfall can gradually carry away supporting soil beneath sidewalks and driveways. As the underlying material erodes, concrete may crack, settle, or become unstable. Addressing the water source is an important part of permanent repairs.
Frequently Asked Questions About Erosion / washout
What is erosion or washout beneath a sidewalk?
The removal of soil or base material by flowing water, which takes away the support the concrete depends on.
Where does the water come from?
Poor surface drainage, misdirected downspouts, leaking water or sewer lines, and heavy rainfall running along the same path repeatedly.
What are the symptoms?
Settling flags, rocking slabs, cracking, and sometimes visible voids or soil loss at joints and slab edges.
Why must the water source be fixed first?
Because replacing concrete over an active washout only buys time. The new slab loses support the same way.