Crawlspace & Attic Mold Can Spread Unnoticed in a Home

We encounter mold in crawl spaces and attics quite often. Crawl spaces are often engineered or built incorrectly and, as a result, they do not breathe and remain damp, dank places. Also, attic decking become moldy when roofs leak.

Mold growing in an attic or crawl space might be out of sight and out of mind, but it is spreading all the while. And, what grows in these areas won’t necessarily stay in those areas. Mold can move into the rest of the house.

With the right conditions, including moisture, it only takes 24 to 48 hours for mold spores to take root as an infestation. Crawl spaces and attics provide conducive conditions for mold growth, including darkness and moisture.

As an aside, there is a debate about how to best handle the conditions in these spaces.  Some opinions involve adding ventilation, adding HVAC, completely closing them in, etc., but it really depends on the situation, so it is important to make an educated decision before changing the dynamic of your crawlspace or attic area. For example, on one hand, ventilation can deter moisture. On the other hand, the movement of air can carry mold spores and temperature differences between outside air and air within the space can cause condensation. It can also create unwanted negative or positive pressures in other areas of the home. This can create another unwanted set of issues.

You might ask if it really matters if there is mold in your crawl space. Yes, it can pose major health threats. There is a risk of mold from a crawl space spreading to the rest of a house because it can spread into the subfloor, joists, girders and framing, and the tiny spores can then ultimately circulate to the rest of a house by rising with warm air. If your crawl space is moldy, we can treat it, but it is also important to determine the cause and then fix the issue so that the mold will not return.

Mold Prevention

Check to see if there are any holes or cracks in the foundation or the ceiling of the crawl space. Those should be repaired. Also, a barrier should be placed atop the ground and up the walls of the crawl space, such as plastic sheeting, to hold moisture from the ground at bay.

Critters seeking shelter can create openings for mold to enter an attic or crawl space. Walk the perimeter of the house to check for holes. You may have an unwelcome tenant.

Also, look to see if there are gaps or sags in insulation, which can indicate a moisture problem. Remove any wet insulation and locate the source of the leak.

Check to see that gutters and rain spouts are working properly to channel water away from the foundation and crawl space. Similarly, a leak from a pipe within the home could be dripping water into the crawl space. In addition, a flooding event means water swept under your home, leaving plenty of moisture behind.

Finally, remove debris such as scattered wood and trash left by the construction crew. You would not believe what they leave behind! We’ve been under houses that look more like a trash dump than a crawl space. This debris sits on the damp ground under the house and becomes very moldy.

Remediation Process

If you find mold, please call us in. Small amounts of living or dead mold can still cause health issues if not removed properly. Mold remediation is a serious project and homeowners should make sure they are comfortable with the process and protocols that a remediation company uses. A key consideration is what kind of cleaning solution is going to be used. We use an environmentally friendly antimicrobial solution to kill mold and thwart growth.

Your safety will be ensured by proper containment as well. We typically can keep a family and their pets in their home with limited disruption while we work in an affected area. Our work is followed up by independent testing. Once the air quality results show that our work was a success, then we consider the job done.

For more information, contact us at

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