Preventing Basement Moisture and Mildew

In order to prevent basement moisture in your home you will need to inspect your basement, starting with the foundation walls. Basement walls that leak or let moisture seep through them will allow mold and mildew to grow rapidly. By following the few simple steps listed below, you can ensure that your basement stays dry. 

You Will Need:

  • Utility Knife
  • Caulking Gun
  • Caulking
  • Waterproof Paint
  • Polyurethane Foam Sealant
  • Dehumidifier
  • Florescent Spray Paint

Step 1.  Inspecting Your Basement Walls

Although basements look and feel dry, they are still a very damp place that encourages the growth of mold and bacteria. You must ensure that your basement is as dry as possible. One of the best ways to do this is to inspect your basement foundation walls for any sign of obvious defects, which could include cracks in the foundation walls, small holes that lead to the outside and cracks under or around the sill plate where the foundation meets up with the beams of the house. Take your florescent spray paint and place a little mark so that when you return to do the repairs you will know where to find them.

Step 2.  Repairing Cracks in Foundation Walls

You can start the repairs with the cracks you find in your foundation. These cracks allow rain water and ground moisture to seep into your basement and create a moist environment. Using your polyurethane foam sealant, simply fill the crack until it is slightly bulging out. This will ensure a good seal and once dry, you can return and use your utility knife to trim the excess away.

Step 3.  Repairing Holes in Foundation Walls

Make your way around the basement again to caulk and fill in all the holes you found located in the foundation walls. Many of these holes will take place around wires, cables, vents, and heating pipes. Ensure that you apply enough caulking to completely close off any holes that allow daylight or wind to blow through them. A good test is to take a candle and check that air is not blowing through anywhere. If it is, your candle will flicker in the breeze.

Step 4.  Sealing the Foundation Walls

Paint the walls in your basement using waterproof basement paint. This will ensure that the moisture stays on the outside of your basement where it belongs, not inside where it promotes mold and mildew growth.

5.  Installing a Dehumidifier

In many cases, after the repairs have been completed to prevent basement moisture, you can feel reasonably secure that the moisture problems will not promote the growth of molds and mildews. A final step of caution is to install a dehumidifier, which will remove most of the remaining basement moisture from the room and prevent mold and mildew. Dehumidifiers can be purchased at most home care centers and hardward/lumber stores.

6.  Using Light Instead of a Dehumidifier

In many instances, when basement moisture is not really a big concern after the repairs have been completed, simply leaving a light or two on can have the same effect as installing a dehumidifier. Mold and mildew like to grow in dark places, and by leaving the lights on, you inhibit their natural growing space.