Many unfinished basements will have a concrete or cement floor. Even when properly installed, and reinforced, settling of the home over time, as well as water below the floor can lead to small cracks in the surface. In addition to being visually displeasing to the eye, these small cracks in a cement basement floor can lead to more damage over time.
As water begins to seep up through the cracks, the cracks will widen, mold and mildew will flourish in the basement, and a homeowner has a much bigger problem on his hands. Repairing these cracks before they become a problem is an easy, do-it-yourself job that any homeowner can tackle, thus saving themselves more time and money in the future.
Examine the Crack
Cracks in a basement floor can take on many shapes and sizes. The first thing to do before beginning a repair is to examine the crack. Be sure that there is no water seeping up through the crack, and no moisture surrounding it. A very thin, hairline crack, with some moisture can be sealed, however flowing water cannot. Water coming up through a large crack is a much bigger problem, and should be seen to by a professional right away to avoid further damage.
If the crack is dry, take a look at its size. Hairline cracks require a different type of repair than a larger crack will. If there is loose or crumbing concrete, this will need to be cleared away first, as well, so locating all the cracks and examining their state will help the homeowner gather the right supplies.
Repairing a Hairline Crack
Many basement floors are subject to these small, thin cracks over time. Before making repairs, to hairline cracks, be sure to wash the floor well, to remove dirt and oil. No fillers will adhere well to a dirty floor, so this step is extremely important.
If the cracks are dry, purchase a tube of concrete filler. These are available in epoxy, latex and vinyl at most home improvement stores. A caulking gun and a thin trowel will be helpful in spreading the filler evenly. Simply apply the filler directly to the crack, and work it in well with the trowel to ensure an even patch.
If the hairline crack has moisture around it, a hydraulic cement will be required. This is available in a dry powder, which is mixed at home with water. Simply mix the cement according to the manufacturer’s specifications and spread a layer of it onto the crack with a trowel. Be sure to cover all areas of the crack, and work it in well, to keep out further water infiltration.
Repairing a Larger Crack
Larger cracks, which can be formed due to frost heaves or house settling, can still be repaired by the homeowner, provided they are dry. To repair these crack, a hammer and chisel will be required to remove any loose or crumbling concrete from the edges of the crack. Hold the chisel at a 45 degree angle to the crack and hit it with the hammer to dislodge the loose concrete. Repeat this on both sides of the crack for its entire length to ensure good adhesion from the patch.
Use concrete filler and a trowel to fill the crack. Deep cracks may take more than one application of filler to completely fill the crack. Begin by squeezing the filler into the crack and troweling it smooth. Allow it to settle, and watch for sagging or settling. If this occurs, add more filler until an even surface has been achieved.
Sealing the Floor
Allow any repairs made to the basement floor to cure for 24 hours. For large cracks, check back after 8 – 12 hours to make sure that no additional sagging has occurred; if it has, simply add more filler.
Once the filler has cured, it’s important to seal the patches. Apply a polyurethane sealer with a brush or roller in two to three coats, allowing it to dry thoroughly between each coat. This will help stop additional moisture from getting in, as well as impede staining.
Always repair cracks as soon as possible to ensure that further damage does not occur over time. Occasional resealing of the entire floor can help to prevent stains and water damage, as well, and should be part of the home’s maintenance program.
Work carefully, consult a professional as needed, and help the basement floor retain its integrity for the life of the home.
Sarabeth Asaff - Sarabeth Asaff is a freelance writer and artist with a passion for cooking and good food. Growing up in the kitchen of her Lebanese ...
