Once you've determined the cause of the problem, it's time to repair the crack. You may be tempted to simply hide the eyesore by strategically placing furniture or a painting in front of it. However, fixing the crack will not only prevent the crack from growing and causing further problems, it will also retain the integrity of your home.
Cracks in Concrete
Cracks that appear in the foundation or basement walls of a home should be repaired quickly and properly by a professional, or even yourself.
As these walls tend to be constructed out of cement, avoid using caulk or hydraulic cement. The end result may look good, but both materials offer only a temporary and superficial solution as they still allow water and moisture to enter the crack. Rather, choose something that fills the crack and protects it from moisture. Look for do-it-yourself products on the market that feature injections of polyurethane or epoxy which can expand to fill the crevice.
Before repairing any crack properly, make sure moisture and dirt have been cleaned from the area and flaking concrete is chipped away.
Cracks in Plaster and Drywall
Most cracks that appear in the interior walls of your home are easy to repair and generally do not require the assistance of a professional. The threat of water worsening the problem is not as prevalent as when it is located in the wall of the basement or foundation; regardless, it is best to check that it was not caused by leaks (or any other type of structural problem).
Interior walls are generally constructed out of two materials: plaster or drywall. Plaster crumbles easily, while drywall can support nails and screws.
Like cracks in concrete, remove moisture, dirt and crumbling plaster/drywall from the area. To repair a crack in a plaster wall, a patch compound or plaster paste can be used. Plaster tape will be required if the crack is exceptionally wide. Drywall utilizes spackling. After filling, remember to sand down the area so that painting over it results in a smooth finish.