Basement wall repairs are best done with a caulking gun and an epoxy-based resin. To fix most cracks, particularly those in mortar between concrete blocks, you can insert the tip of the epoxy tube into the crack and pull the trigger to apply the sealant. Many people have tried to repair their cracks themselves or have hired a cheap contractor to do so, only for the crack to leak again months or years later, costing them more money and causing further damage. However, for professionals, it is a very quick and easy problem to solve. Some waterproofers will suggest digging around the entire outside of the wall where the crack appeared and installing a waterproof barrier.
Fortunately, many foundation cracks aren't serious enough to require professional attention, and repairing a foundation crack can be a DIY task as long as the crack doesn't compromise structural integrity. Various masonry repair products, such as hydraulic cement, can be used to fill cracks in concrete walls. Liquid Concrete Repair Tubes (LCR) are also available; these are viscous epoxies that come in a putty-type cartridge with seven plastic injection ports that deliver the CSF deep into the crack. The crack can be up to ½ inch wide and is not yet a major issue other than allowing moisture, odors and gases in. To make sure that a crack doesn't indicate a more serious problem, it's best to have it checked by a foundation contractor or structural engineer.
However, some general rules can help you decide whether or not you should be concerned. Additionally, cover the entire flange of each injection port with crack sealant, leaving only the extended part of the neck visible. Typically, these types of cracks don't threaten the structural integrity of the house, but they do create an entry point for groundwater, insects and radon gas. This becomes an issue when the soil surrounding the basement begins to push against the walls, moving them inward and causing bowing and cracking. Repairing a foundation crack larger than ½ inch can be done yourself, but if the crack is due to something more serious, you should first seek professional advice.
If you only had cracks on your steps, you could go ahead with basement finishing work as this kind of crack is normal due to settlement. However, if there is a horizontal crack that has bent the wall inwards, this is a sign of a very weakened wall that may fail. Easy, economical and easy to do yourself, the main purpose of this concrete repair is to prevent water from seeping into your basement. These problems also take the form of horizontal or staggered cracks along the foundation wall, diagonal cracks in the corners, inward protrusions and sloping walls at the top or bottom. One of the best methods for sealing a leaking wall crack in North Carolina is to use a high viscosity polyurethane polymer.