How to Replace a Concrete Stack Retaining Wall

Wall Less Than Two Feet Tall

• Concrete stack retaining walls less than 2 feet may be dry laid. This means that the blocks have no adhesive holding them in place, which makes it simple to take the block walls apart. To remove a dry-laid concrete stack retaining wall, simply start at the top and lift the blocks from the wall one by one. If you get resistance when trying to remove the top blocks, look down inside the blocks. Some walls may have metal rebar inside the cavities for extra durability.

Walls Greater Than Two Feet Tall

• Concrete stack retaining walls of heights greater than 2 feet generally use some type of adhesive on the exterior, even if the blocks themselves were stacked dry. If the walls do have this exterior coating, they require some work when you want to remove them. A chisel and hammer should be sufficient for chipping the adhesive away from the exterior of the wall so that you can remove individual blocks. If you would like to take the entire wall down, however, using a sledge hammer to knock the wall down is a more efficient method.

Underground Blocks

• The blocks that you see above the ground in a concrete stack retaining wall aren’t the only blocks that keep the wall standing. At least 6 inches of blocks--likely more--lie below the ground in a trench. You can use the same basic method to remove blocks from this trench that you used on the rest of the wall. Dry-laid blocks can be lifted out of the trench individually, while adhesive stack retaining walls require chiseling or breaking.

Replacing the Wall

• Once you remove all of the block pieces from a concrete stack retaining wall, you can replace the wall with new blocks or use a new type of building material, such as stone, brick or railway sleepers. The new wall can be built in the original trench as long as the bottom of the trench remains level, though you may need to widen the trench slightly to accommodate materials that may be wider than the original concrete blocks, such as the sleepers. Check the first row of concrete blocks in the trench with a builder's level to ensure a level wall.

Building Details

• Several building procedures help ensure the stability of a retaining walls, including staggering the seams of the rows as you lay the concrete blocks, placing pieces of metal rebar into spaces in the concrete blocks, and using mortar between rows of building materials, or an outside adhesive coating, to prevent deterioration. Concrete retaining walls also generally do not directly touch the dirt that they hold back, but have a vertical layer of gravel that separates the wall from the dirt.