How much does a retaining wall cost?

Retaining walls come in two categories: 1) Over 4’ and 2) Under 4’. Why?

1) Retaining walls over 4’ by code must be engineered. A geotechnical engineer* will be required to test the soil and design the wall. The engineer takes liability for the wall and thus 3 different engineers will not necessarily design the same wall for the situation. Engineers will usually design Redi Rock Block, Soldier Pile, or Rockery Walls depending on the soil. Any contractor installing walls over 4’ tall require additional credentials and insurance as well to handle the increase in liability for such walls.

2) Retaining walls under 4’ can be built without a permit and without engineering, however, it’s important to use an experience contract because a 4’ wall can still fail if the correct blocks are not used. At a minimum and pre engineered block should be used. For our economy block we like mutual materials Manor Stone block. It comes in 3 colors, it’s easy to install, and it gets the job done. A 100’ long wall at max height will cost between $13,000-$16,000 depending on the slope of the grade and the demolition required to install the block.

Terraced 4’ retaining walls to total a height over 10’ in elevation change.

Another sub-category of wall is dry stack and poured concrete. Poured concrete is a whole other beast as anything over garden bed height should be engineered and design with a footing, et cetera. In general, for the poured concrete wall the footer will have to be trenched , forms installed, concrete poured, and then a skim coat will have to be overlayed to get that smooth modern look people want with concrete retaining walls. With perfect conditions that same 100’ long wall will cost anywhere from $20,000 to $30,000. A dry stack wall is a home depot DIY type gravity wall in which you literally stack roman cypress or similar stones. These are the cheapest walls you could install and a 100’ wall at 4’ (not recommended install a dry stack wall over 2’6”) would be between $10,000 to $20,000 depending on material. For example natural basalt rock dry stack walls are more expensive due to materials where as a cobble block from home depot will be inexpensive.

Poured Concrete retaining wall in Bellev