How to Repair a Stair Step Crack in a Block Wall

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Things You'll Need

  • Scrub brush

  • Water

  • Concrete repair kit

  • Steel bar supports

  • Masonry screws

  • Brackets

  • Hammer

Block walls can crack from settlement and ground pressure.

Concrete blocks are used a lot in construction as foundation walls in basements. These work just fine, except that you cannot always predict how the ground around them will move or shift over time. In some cases, the ground can settle under or push in on the walls, creating cracks. The gaps in the wall can run in different directions, but one common crack is called a stair step, where the crack follows the mortar at a diagonal, spreading across many blocks. This is fixable in many cases, but a professional should inspect it before you repair to ensure that the wall doesn't need to be rebuilt.


Step 1

Clean out the crack as best you can with a scrub brush and water. Let this dry for a couple days.

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Step 2

Insert the ports that come with the patch. Place them in the crack so that the plastic ring around them is flush to the wall. Set them about 8 inches apart.

Step 3

Coat over the crack with the epoxy glue. This will seal it shut so that when you squeeze the patch into the ports, it won't flow out. Let the glue dry according to the package.

Step 4

Locate the lowest port and insert the tube of patch material. Squeeze the tube until the formula starts to flow out the next port.


Step 5

Put the cap on the port and move on to the next one. Repeat this until you have squeezed the patch material into all the ports. Let this sit for a couple of days before removing the ports. In the meantime, you have another task to complete.

Step 6

Brace steel bar supports at a 45-degree angle into the ground or screw them to the concrete floor with masonry screws using a bracket to anchor them. Connect the other end to the wall. Wedge them as forcefully as you can on the wall, then use anchor brackets to attach them. This needs to be done if the issue is a matter of bowing due to ground pressure from the outside.


Step 7

Remove the ports with a hammer tap to the side of them. When removed, fill the leftover holes with a bit of the repair patch and allow it to dry.


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