A cinder block retaining wall is a choice that requires less investment compared to a solid concrete wall, but it's not without its imperfections. However, repairing requires just a few masonry tools and no heavy masonry equipment.

When a concrete retaining wall settles, cracks may form, and the same is true with a cinder block retaining wall. When cinder blocks crack, it's generally along the mortar.

With time – and exposure to the elements – the blocks that make up the cinder block retaining wall may deteriorate due to weather conditions.  That means you might need to fix cracks or replace whole cinder blocks.

Follow the easy steps below to effectively fix a cinder block wall. 

Step 1 – Patch the Cracks and Remove any Damaged Cinder Blocks
To fix the cinder block retaining wall, you have to remove what’s broken. For cracks, use a wire brush to remove loose pieces of concrete and mortar. You want the site to be as clean as possible.

In the event you have to remove a whole cinder block, such as when a crack extends into one, then the job is somewhat harder.

Use a cold chisel to chip away at center of the damaged block. Remove as much as you can, carefully chiseling off the mortar from the surrounding blocks without chipping the blocks.

Step 2 – Cut that Rebar
Once the damaged cinder block has been efficiently chipped away, you'll notice rebar that was running through it and that holds the retaining wall in position nice and sturdy.

The rebar from the removed block makes it impossible to put another one in place. Use a metal cutting blade such as this  one from Husqvarna, and cut the rebar as close as possible to the top and bottom of the cinder block you removed.

The rebar is through the whole wall, so cutting it in the space of one block will not hurt the stability of the wall.

Step 3 – Mortar Up

Mix up a batch of mortar. You want it to be the consistency of peanut butter. If you're fixing cracks, then place the mortar in masonry mortar bag and completely fill the cracks with it. Use a trowel to remove excess of a 1/8” layer.
If you're replacing a whole cinder block, then you may need a larger batch of mortar, so plan ahead. Use the trowel to put mortar inside the hole where the cinder block used to be and the edges of the bordering blocks.

Slide new cinder block in position and push it in place, tapping with a block of wood and rubber mallet, if necessary.

Step 4 - Make it Tidy

Mortar will stream out from the space. When this occurs, use the masonry knife to scoop/catch the excess. You may also fill the gaps with mortar using the pastry bag method. If there's a great deal of excess mortar coming out, use that trowel. Smooth mortar between your new cinder block and the surrounding to the same depth below the surface of the wall as the other joints in the area of the repair. Allow to cure and you’re good to go!

Always get at least a few bids from local masonry contractors for a professional result that lasts longer.