Fixing Cracks In Concrete Walls

An easy, long-lasting solution for a leaking basement wall crack.

Cement, sand, gravel, and water are the primary components of concrete. The remaining ingredients cure into a hard, monolithic slab as the water in the slurry evaporates. Unfortunately, the curing process induces minor shrinkage of the mortar, which also results in hairline cracks.

Do Cracks in Walls Indicate a Structural Problem?

When a building sits or the earth under it shifts, larger stress cracks appear. These cracks don’t normally jeopardize the house’s structural integrity, but they do provide an entry point for groundwater, rodents, and radon gas. We’ll teach you how to fix cracks in poured concrete walls in this report.

Do not attempt to patch big, recurring cracks or bulging walls yourself if you find them in your home. Call in a structural engineer for an in-depth assessment of whether the cracks suggest a more severe structural concern.

Several masonry patching materials, such as hydraulic cement, are effective at covering concrete wall cracks. However, if the base or retaining wall starts to change slightly after a few years, these items will fail, leaving you with no choice but to chip them out and start again.

Before Your Begin

Check to see if the crack is dry before you start. If the crack is wet, use a blow dryer to dry it, then wait 15 minutes. Proceed with the patch if it stays dry.

If the dampness returns, though, water will continue to seep through the gap, and you’ll have to wait for it to dry out on its own.

Concrete Wall Crack Repair in 8 Steps

Use an Epoxy-Injection System for Basement Wall Crack Repair

We fixed an 8-foot-long break in a concrete wall that was pouring water into the basement during times of heavy rain. We used a Polygem Liquid Concrete Repair Package ($60) epoxy-injection device to permanently repair the break.

A two-part epoxy crack sealer, two 10-oz. tubes of Liquid Concrete Repair (LCR), a viscous epoxy that comes in a caulk-type cartridge, and seven plastic injection ports deliver the LCR deep into the crack are all included in each package. Each package includes enough material to fill a 1/16-inch wide x 8-inch deep x 8-foot-long crack.

Step 1: Scrub it Clean.

Using a wire brush, wipe the crack clean of any loose mortar, wax, or old filler. Using a shop vacuum, clear all dust and dirt.

Step 2: Use a Nail to Align Injection Points

Partway into the split, insert 3-in. (10d) finishing nails, spaced 12 in. apart. They’ll help you line up the injection ports with the crack.

Step 3: Mix the Two-Part Epoxy Crack Sealer

To prevent leakage, open the two tubes of epoxy crack sealer and scoop out equivalent quantities of Part A and Part B using two different sticks.

Using a clean putty knife, mix the two pieces on a scrap board until a consistent grey color is achieved.

Step 4: Spread the Sealer onto Base

Apply a small amount of sealer to the base of one of the plastic injection holes, taking caution not to block the hole. Push the port against the wall by slipping it over one of the nails protruding from the crack.

Mount the remainder of the ports in the same manner.

Step 5: Mix and Apply a Larger Batch of Epoxy Sealer

Then, using a 1 1/2-inch-wide putty knife or margin trowel, add a much larger batch of epoxy sealer to the whole crack.

1/8 in. wide and 1 in. on each side of the break, apply the sealer. Also, use the crack sealer to cover the entire flange of each injection port, leaving only the extended neck section uncovered. With a paintbrush soaked in mineral spirits, smooth out the sealer and feather the sides.

When you can get to the other side of the building, check to see if the break goes all the way in. If it does, add a crack sealer to it as well. Enable 6 to 10 hours for the sealer to cure before injecting the epoxy.

Step 6: Dispense the LCR Epoxy

Using the plunger rod that comes with the package, thoroughly mix the LCR epoxy. In a caulk gun, put the LCR cartridge. Dispense the epoxy into the crack starting at the lowest injection port.

Step 7: Fill Up the Ports

Squeeze the trigger again before epoxy continues to ooze out of the port immediately above. Remove the gun and cover the port that has just been loaded.

To dispense the epoxy, insert the cartridge tip into the oozing port and squeeze the trigger. Repeat for the remaining ports, plugging them in one by one before going on to the next.

Step 8: Cut Necks of the Ports

Enable the LCR to cure for five days before hacksawing the ports’ necks off. If required, a small amount of crack sealer may be used to repair the severed ports.


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