Retaining Wall Replacement — Failed Wall Torn Out and Rebuilt

A retaining wall leaning or bulging after winter is telling you what failed. Frost does not push on dry soil; it pushes on wet soil. When a wall comes out of the spring thaw tipped forward or bellied out in the middle, water has been sitting behind it with no drainage stone or pipe to carry it off, and each freeze shoved it a little further. A wall that moves every spring keeps moving.

A retaining wall is replaced when the problem is under it or behind it, not in it. A wall leaning along its whole length, a face that bulges out at the middle, courses that have slid off the ones below, or a section that has already fallen is a base or a drainage failure, and there is no way to fix either with the wall standing. The block, stone or timbers come down, the wet soil behind them comes out, and a new wall goes up the way the first one should have been built. Most of the walls we replace were built with no drainage stone, no pipe and a first course set on topsoil, and they lasted about as long as that gets you in Minnesota.

What can be reused depends on what the old wall is made of. Segmental block that is not cracked or spalled is cleaned and stacked and goes back in the new wall, or into a lower wall or a planter elsewhere on the lot, which is the biggest saving in a replacement. Boulders are almost always reusable. Cap units are often glued and break coming off, so caps are usually new. Old drainage stone, if there was any, is silted shut and gets hauled with the soil. Rotted landscape timbers and railroad ties are never reused; they go to a facility that takes treated wood, and that job has its own page. Poured concrete and mortared block are broken up and hauled as clean fill.

The rebuild is the same as a new wall: a trench to firm soil, compacted class 5, a level first course partly buried, block or stone stacked with its setback or batter, clean drainage stone with a perforated pipe to daylight, filter fabric, geogrid where the height calls for it, and backfill compacted in lifts. If the old wall was tall, held up a driveway or patio, or was above the height where your city requires an engineer, the replacement gets a structural engineer's design and a permit before we dig; a wall that failed once is a wall the city will want to see done right. Replacing a wall disturbs everything around it: the lawn above, beds, a fence line, a patio edge. We tell you what comes out and what goes back at the site measure, and a skid loader or mini excavator needs a path to the wall.