How to Repair a Masonry Block Wall

  • 2-4 hours
  • Beginner
  • 25-75
What You'll Need
Cement blocks

There are plenty of reasons why a masonry block wall is used around your home. Most of the time these walls are used as retaining walls, or for building up outbuildings for sheds and garages. After a few years of sitting in the weather, you may find some cracks, or some of the blocks crumbling or breaking. Repairing the masonry block wall is something that can be done easily with tools and a few hours of your time. Some of the work can be strenuous, so if you have any problems with heavy lifting you may want to get help or hire a professional.

Step 1 - Determine Exact Problem

There are some problems that cause the cracking, or the breaking of masonry blocks that may have to be taken care of before you repair the masonry wall. Is frost heaving the wall during the winter months? Is there too much pressure behind the retaining wall? Is the wall sitting in an area where there is a lot of water runoff? Find out these things so that you can fix them to stop any other future repairs.

Step 2 - Repair Simple Cracks

If you notice that your masonry brick wall is only suffering from some cracks in the mortar, or in a specific block, you can fix this with a simple repair. Clean out any of the chipped mortar with a brush, or chisel. Do not break any off, just remove the parts that are already crumbling. Mix up a small amount of mortar and push into the opening. You can also use some mortar in a tube that can be applied with a caulking gun. This is for smaller cracks, but can make the repair easy and quick.

Step 3 - Replace Block

This can be done when the block is situated in the center towards the top. If the block is sitting on the bottom of the wall, you will want to find a professional to do this project.

Step 4 - Dig Out Mortar

If you decide to remove the block you will need to start by chiseling out the mortar around the block. This can take some time, but a hammer and chisel will help to chip out the mortar. Do the sides of the block first so you can place some wooden pieces in the hole to act as supports for the upper tiers.

Step 5 - Mix Mortar

You will need to act fast once you remove the block. This means that you will have to mix the mortar before it is removed. Follow the directions on the bag of ready mix and use a bucket for this.

Step 6 - Replace Block

Once the mortar is ready you can the remove the block out of the masonry block wall. Set it down and clean out the hole where it was. Place a layer of mortar on the bottom of the hole and then place the new block on top of the mortar. Squeeze in mortar around the block until it is packed in. Before it dries completely run your trowel along the edge of it to give a finished look.