Why do retaining walls fall over?

Many factors can cause wall that look as though they were designed by the architects of Pisa.

The first thing is pressure. If the load on the wall is too heavy, it will apply pressure on the wall and cause it to start tipping, and maybe even fall over.

Anyways, when the load of a house, or foot traffic, or something, is heavier than the load the wall was designed to carry, the wall starts tipping. Plain and simple.

Or this could happen. A wall is built. It is built on a not perfectly graded base. So it is about to tip. All it needs is someone to look at it the wrong way. Someone looks at it the wrong way. It starts to lean.

Or this could happen. A wall is built, but the builders build it backwards, so that it’s interlock retaining system (which is directional) is pointing in the wrong direction. That causes a lot of tipping!

Or this could happen. A wall is built, but the builders forget, or worse yet neglect to put in the little pins to help the wall interlock. Needless to say, that is not good.

Or this could happen, and often does. It is probably the greatest cause of failure that people do not know about:

When you build a wall of a certain height (opinions differ, but four feet is what I say), you are commanded to use a certain substance called geogrid. Many people do not understand how it works, so they don’t use it.

Use it. If you have a retaining wall that is retaining ANY significant load you need to use it or it will likely fall over.

So in most scenarios it has to do with poor engineering (planning) or poor construction methods.

And in many states and countries and provinces and cities, walls over four feet require an engineer’s stamp and maybe a permit from the city. So make sure you are careful when you are building a wall.

Be very careful. Because the wall could collapse and then your house could collapse and everyone could die. That would be very unfortunate.