How to Patch Basement Concrete
Concrete basements are designed to provide a clean, dry area in which to store things. Sometimes, however, concrete cracks, due to shrinkage, will appear in the basement walls, which can allow water to seep into the area. While this is not usually a structural issue, you should not ignore these cracks, but repair them by patching, which is a low-cost and efficient way to solve this problem. Does this Spark an idea?
Things You'll Need
- Safety glasses
- Rubber gloves
- Wire brush
- Broom
- Dust pan
- Plastic injection/surface ports
- Small plastic trowel
- Epoxy paste
- Caulking gun
- Polyurethane foam cartridges
- Plastic mixing nozzle
- Plastic hose assembly
- Putty knife
- Hammer
- Scraper
Instructions
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How to Patch Basement Concrete
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1
Put on safety glasses and rubber gloves before beginning this project.
Use a wire brush to clean the existing crack in the basement concrete wall and dislodge any debris. Sweep up the debris with a broom and dispose of it.
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Surface ports will be placed at distance of one inch apart for every inch of thickness of the concrete wall. This is usually eight inches.
The first surface port will be placed at the lowest end of the vertical or horizontal crack.
Start from the beginning of the crack, and measure eight inches. Use a grease pencil to mark the surface port placement. Measure and mark the rest of the crack.
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3
Remove the cap from the surface port and use a trowel to apply epoxy paste to the bottom of the first surface port.
Place the first surface injection port directly over the center of the lowest part of the crack and press to adhere it to the wall.
Repeat all surface ports have been placed on the wall.
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4
Use the plastic trowel to seal the crack and the ports with an epoxy paste. Apply the paste 1/8 inch thick and 2 inches wide. This will bond the ports to the surface, which will allow for the polyurethane foam to be injected into the crack.
Do not try to push epoxy paste into the crack. Instead, just seal the surface.
Allow the paste to cure. Curing time will take approximately 20 to 45 minutes, or until stiff to the touch.
If the crack goes above the basement wall, you will need to apply the epoxy paste on the outside of the foundation, above the soil. Allow the same curing time.
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5
Load the cartridge of polyurethane foam into the caulking gun.
Attach a plastic mixing nozzle to the cartridge with a plastic nut. Firmly attach the wide end of the plastic hose assembly over the mixing nozzle.
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Begin injecting the ports with the polyurethane foam. Attach the small end of the hose assembly to the lowest surface port. Ensure that the hose is firmly in place.
Begin injecting the polyurethane foam slowly. When you notice the foam starting to ooze out of the port above, use the pinch valve on the hose assembly to turn off the hose.
Remove the hose from the surface port and cap the port.
Move to the next port and repeat the procedure until the entire crack has been injected with the polyurethane foam.
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7
The foam will expand and protrude from the crack. Wait three to four hours and remove it from the surface of the wall with a putty knife.
Remove the surface ports by striking them downward with a hammer.
The remaining surface seal epoxy can be painted or removed with a scraper.
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Tips & Warnings
Before beginning, put on two pair of rubber gloves. If the outer gloves become unusable, peel them off, and you will still have a clean pair of gloves on your hands. Use a slow and even pressure when injecting polyurethane foam. It is not uncommon to spend three to four minutes at each port injection site.
Do not allow the epoxy paste to block the surface port opening. Otherwise, you will not be able to inject the polyurethane foam. Blowouts or leaks may occur when filling the ports. These leaks may occur in parts of the crack above or below surface ports. This will not reduce the effectiveness of the procedure. It is simply a result of not allowing the epoxy paste to set properly. To avoid this, allow enough drying time.
