Why Retaining Walls Fail — And What Actually Holds Them Up

A retaining wall holds back soil, and soil gets much heavier when it is wet. That single fact explains most of the walls you see leaning, bulging or stepping apart around the Merrimack Valley — the wall was built to hold dry dirt, and then it rained, or the frost got under it.

Two things decide whether a wall stands. The first is the base: a trench dug below frost line, filled with crushed stone, and compacted in layers. Blocks set on undisturbed topsoil will heave and settle unevenly no matter how good the blocks are. The second is drainage behind the wall — clean stone and a perforated pipe that gives water somewhere to go. Without it, water builds up behind the wall and freezes, and it will win.

Neither of those is visible when the job is finished, which is exactly why they get skipped. The wall looks identical on day one whether or not there is drainage stone behind it. The difference shows up after the first hard winter.

Thinking about a wall, or worried about one that has started to lean? Call Ramirez Hardscapes & Tree Service at (781) 600-9759 for a free estimate — we will tell you honestly what it needs.