Avoiding Mold On Floor Joists This Winter

avoid mold on floor joists this winter

Winter is right around the corner for us here in South Jersey, and much like any other season in South Jersey, the weather can be pretty unpredictable. Lots of rain, humidity, and potential for snow is likely coming our way. A common question that we’ve been receiving is how to avoid mold on floor joists this winter. Most property owners are aware that basements & crawl spaces are prone to excess moisture, which can lead to mold development. However, the floor joists, sometimes referred to as subfloor or “basement ceiling,” can often be overlooked. Unfinished basements and crawl spaces are especially vulnerable, as the foundation walls and floor joists are left exposed.

In most situations, mold on floor joists can be easily avoided. Floor joists & subfloor are often built from unfinished wood, which can hold a lot of excess moisture if left exposed. Floor joists are generally more susceptible to mold growth than foundation walls, as cement is far less porous of a material than wood. Luckily, there are quite a few simple steps you can take in order to avoid mold on floor joists and subfloor without too much extraneous work on your part. Adding these steps into your home maintenance routine can make all the difference when it comes to avoiding mold on floor joists. 

Steps To Avoid Mold On Floor Joists 

In comparison to other areas of your home, crawl spaces & basements tend to experience more moisture due to improper ventilation. This is a common issue in many homes, and it is relatively simple to rectify. Moldy floor joists can be caused by a number of things, including leakage, excess humidity, condensation, and even moisture from the ground can cause mold in unprotected crawl spaces. 

  • Check For Leaks: Routinely check your foundation wall for cracks or leaks every few months. This is a good way to ensure that there is no excess moisture entering your basement or crawl space from the outside. Should you come across any cracks, fill them in as soon as possible. Small cracks that go unnoticed for a long period of time have the potential to cause severe amounts of water damage via slow leakage. Keeping your foundation walls in good condition will help you to avoid mold on floor joists and other areas of your basement or crawl space.     
  • Air Circulation: It is extremely common for basements and crawl spaces to experience improper ventilation. Luckily, this is an easy fix. Installing ventilation and fans to keep the air circulating in these areas of your home can help avoid mold on floor joists. Air circulation and ventilation allows moisture a pathway out of your basement/crawl space, which means that this moisture does not have a chance to settle into your floor joists or subfloor. 
  • Using A Dehumidifier: In more severe cases of excess moisture and humidity in a basement or crawl space, the use of a dehumidifier can make a huge difference. Ideal humidity levels in your home should stay between 35% and 50%. Depending on the square footage of the space, you may need more than one dehumidifier to sufficiently rectify the issue.

What If My Floor Joists Already Have Mold?

Mold can spread very rapidly in the proper conditions. If your basement or crawl space is experiencing excess moisture, there is a good chance that your floor joists and subfloor could have fungal growth. As previously mentioned, this area tends to get overlooked. It is extremely important that you keep an eye on your floor joists regularly, as mold will continue to spread if given the opportunity. The good news is that dealing with mold on floor joists is relatively straightforward. More often than not, floor joists can be remediated properly without having to be removed altogether. In the event that you suspect mold on your floor joists, don’t hesitate to contact a professional mold remediation company in your area. They will be able to assess the damage, as well as design a professional scope of work for remediation should you require it. When it comes to mold on floor joists, time is of the essence. Ensure that your floor joists are taken care of as soon as possible by a professional mold remediation company you can trust.


  • Thomas Duff

    Thomas Duff, the visionary founder of MasterTech Environmental, brings a wealth of expertise and passion to the forefront of our mold remediation and biohazard cleanup mission. With a profound commitment to setting new industry standards, Thomas leverages his hands-on experience and innovative spirit to lead MasterTech Environmental to unparalleled success. Overseeing not only the original Blackwood, NJ location but also the thriving MasterTech Franchise Systems, Thomas champions a tight-knit family of professionals dedicated to serving communities, cultivating honorable trades, and ensuring customer satisfaction. Recognized for our presence on HGTV and DIY Network, Thomas Duff's dedication to excellence has driven our company's exceptional client ratings on Google and other review platforms. With a clear vision, unmatched passion, and a commitment to continuous improvement, Thomas Duff continues to lead MasterTech Environmental into a successful future in the restoration industry.

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