How to Kill Mildew in Your Crawlspace

  • 1-3 hours
  • Beginner
  • 0-100
What You'll Need

In a moist environment, it is easy for a crawlspace to fill with mildew. Mildew can be very problematic. It is unsightly, can cause damage to many materials, and can even be a health risk. Mildew is notoriously hard to eliminate, especially in the long term.

Even if you manage to eliminate a current mildew problem, it is quite likely that your problem will return. Follow these steps to solve a mildew problem permanently without having to worry about recurring problems.

Step 1 - Setting Up

It is possible to kill mildew with vinegar. Vinegar is natural and safe. It releases no toxic fumes. It is also convenient and common. It even works on porous surfaces, unlike bleach. Unfortunately, it is relatively mild and will not always kill all mildew, even after repeated applications. Bring your sponge and vinegar to your crawlspace. Soak your sponge in vinegar.

Step 2 - Cleaning

Apply vinegar to the affected area with your sponge. Allow the vinegar to soak into the affected areas for a few minutes so that it can work its way into the material and kill the mildew. Do so whether or not the material is porous. After a few minutes have passed, wipe the area clean with your sponge. Dead mildew turns white, so you can tell relatively easily whether the vinegar is working.

If you can remove all of the mildew in this manner, great. Sponge over the entire area with vinegar, not just the area that had visible mildew problems, to prevent future problems. Consider yourself done removing the current growth of mildew.

If the mildew remains unchanged, reapply vinegar and wait a few again. If that does not work, reapply and wait for an hour. If that does not work, you will need to use a stronger cleaning agent.

Step 3 - Further Cleaning

If you need something stronger than vinegar, borax is a great choice. Borax does not release toxic fumes and is very powerful; however, it is toxic. Keep it away from children and pets.

Mix 1/2-cup of borax with 1 gallon of water. Use your sponge to apply the mixture to the affected areas, wiping them clean. Wiping a mildewed area several times in this manner should do the trick.

Step 4 - Preventing Additional Problems

Apply of vinegar or borax weekly to combat mildew. A dehumidifier is a better solution to mildew problem. Dehumidifiers keep the area dry, thus preventing mildew from growing in the first place. If your crawl space is damp, feels humid, or seems to generate moisture, a dehumidifier is a good idea.