A retaining wall needs drainage because water that collects in the soil behind it adds a great deal of pressure and weight, which can push the wall out of place or cause it to fail. Good drainage lets water move away instead of building up behind the wall.
Many homeowners think of a retaining wall as just the visible face. But much of what helps a wall last happens behind it and below the ground, where water is managed.
How Water Affects a Retaining Wall
Dry soil already presses against a wall. When soil soaks up rain, it gets heavier and pushes harder. If water has nowhere to go, it can build up and add even more force against the back of the wall.
Water can also wash soil out from under or around the wall, weakening its support. In colder weather, wet soil that freezes and thaws can add movement too. Over time, these forces can lead to leaning, bulging, cracking or collapse.
Signs Drainage May Be a Problem
You can’t see what’s behind a wall, but some clues suggest water isn’t moving away well:
- water seeping through the face or joints of the wall,
- stains, moss or white mineral deposits on the face,
- soil washing out at the base,
- soggy ground above or below the wall, and
- the wall starting to lean or bulge.
These signs don’t always mean the wall is failing, but they are a good reason to have it looked at by a qualified professional. Our article on warning signs of a failing retaining wall covers what else to watch for.
Why Drainage Is Part of the Design
Drainage for a retaining wall is usually planned along with the wall itself. The right approach depends on the wall type, its height, the soil, the slope and how much water reaches the area. That’s why drainage decisions belong with an experienced contractor and, for many walls, an engineer.
Surface water matters too. Gutters, downspouts and yard slopes that send water toward a wall can add to the problem. Sometimes improving how water flows across the yard is part of the solution.
Fixing drainage on an existing wall isn’t a simple add-on. It may involve work behind the wall that should only be done by professionals, since digging near a stressed wall can be dangerous.
Drainage in the Burlington Area
Central North Carolina gets regular heavy rain, and many local yards have clay soils that hold water. These conditions make drainage especially important for walls on sloped lots. A wall that looks fine in dry weather may show problems after a rainy season.
Our concrete retaining wall services consider drainage as part of every project. If you’re planning a new wall or worried about water around an existing one in Burlington, contact us to talk through the conditions on your property.
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