How to Fix & Repair Cracks in an Exterior Cement Wall in a Basement

Examine the crack for dampness. If the crack is wet, dry the area with a blow dryer and wait 15 minutes. If the dampness returns after 15 minutes, wait for the wall to dry on its own before continuing.

Scrub the area with a wire brush to remove loose debris. Vacuum the debris up with a wet/dry vacuum.

Measure 12-inches down from the start of the crack. Insert the end of a 3-inch finishing nail inside the crack at the 12-inch mark. Carefully tap the nail into the wall with a hammer until the nail is about half way inside the crack. Repeat this step at 12-inch intervals.

Open the two-part epoxy sealer. Use a paint stirrer to add a dollop of part A epoxy sealer on a piece of scrap board. Use a second paint stirrer to add an equal amount of part B epoxy sealer to the same piece of scrap board. Mix the two together with a putty knife.

Apply a small amount of the mixed crack sealer on the base of the plastic injection port. Refrain from plugging the hole of the port with the sealer. Slide the injection port over the finishing nails that you hammered into the crack and press the injection port base against the wall. Repeat this step until you have covered each finishing nail with a plastic injection port.

Scoop a large amount of the mixed crack sealer with a margin trowel and spread it over the entire crack. Spread the sealer over the plastic injection port's flange leaving just the neck uncovered. Keep the crack sealer 1/8-inch thick and spread it 1-inch out from all sides of the crack.

Dip the bristles of a paintbrush in mineral spirits. Use the mineral spirit-saturated paintbrush to feather the edges of the sealer. Wait six to 10 hours for the sealer to cure before continuing. Open the LCR epoxy cartridge and install it into a caulk gun.

Insert the caulk gun into the lowest plastic injection port. Squeeze the caulk gun trigger to fill the crack with the epoxy.

Continue squeezing until the epoxy begins to ooze out of the port above the one you are currently working on. Remove the caulk gun and install a plastic plug into the plastic injection port.

Repeat Steps 8 and 9 on the remaining plastic injection ports. Let the LCR epoxy cure for five days before sawing off the neck of the plastic injection port with a hacksaw. Saw the neck as close to the wall as possible.

Scoop a small amount of the epoxy sealer mixed in step 4 and spread it over the small hole left behind after sawing off the plastic injection port. Spread the sealer as smooth as possible and let dry for 10 hours.