Can My Crawl Space Cause Moldy Baseboards?

Are my moldy baseboards caused by the wet crawl space? Many homeowners do not consider the crawl space to be a part of the home since it is not an area they frequent. Many homeowners forget they have a crawl space unless there is a problem. A moldy baseboard can be an indication of a problem in your crawl space but there are other areas to look as well.

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Moisture Causes Moldy Baseboards

I am not saying that all moldy baseboards are directly linked to the crawl space. Moisture is one of the reasons mold is able to thrive in our home. That moisture can come from many areas. High humidity, ice machine line breaks, toilet backs up, washer or tub overflows. All of these water issues can lead to mold if not addressed quickly.

Mold can begin to grow within 24 to 48 hours after a flood or moisture problem. Drying the wet areas as soon as the water intrusion occurs is the best way to prevent a mold problem. Many times this will include large dehumidifiers, wet/dry vacuum and fans. But what happens if the crawl space has been humid all summer and the problem was not addressed quickly?

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High Crawl Space Humidity Enters Your Home

The stack effect or chimney effect explains the air movement inside buildings. There are many factors and variations of air movement depending on storms, seasons, and air sealing. But the simple explanation is air enters the crawl space and exits the attic. This is why a humid crawl space is having a negative effect on your living space and causing moldy baseboards.

While a wet crawl space allows high humidity and potential mold to enter your home, a dry crawl space can help keep your home dry. This is why crawl space encapsulation with a dehumidifier and water management is so vital to the indoor air quality of your home. Adding proper insulation and air sealing will improve energy efficiency as well and minimize the stack effect.

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HVAC Humidity is Too High and Affects Baseboards

A humid crawl space can contribute to wet air blowing through your duct-work. The air conditioner is removing moisture while cooling the air to deliver to your living space. If your crawl space is wet, the AC has to attempt to remove more moisture. This is a losing situation for your HVAC system. Typically, HVAC units do not run long enough to bring high humidity below 60%.

If the air blowing out of your HVAC registers is above 60%, the entire home is becoming humid. As the AC system runs it pumps more humid air into the home while furniture and building materials absorb excess humidity. The moldy baseboard is suffering from a two fold attack of moisture. The crawl space is hitting the baseboard with moisture via the stack effect and the humid air of the living space is contributing as well.

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Prevent Mold on Baseboards

Moldy baseboards need to be replaced but replacing the baseboards without stopping moisture is a waste of money. We recommend having the crawl space inspected for moisture issues. If the crawl space is in good shape then the moldy baseboards could be wet from an appliance or plumbing leak.

Another source of moisture could be a leak from exterior walls or the roof. Water can run down walls or humidity build up inside the walls and affect the baseboard. Address all water intrusion and high humidity issues as soon as they are discovered to create a home with better indoor air quality.

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What Next?

Do you need help with mold removal, crawl space encapsulation, crawl space insulation, vapor barrier, waterproofing, or controlling humidity in your crawl space and you live in Alabama, Georgia, Delaware, North Carolina, South Carolina, Tennessee, or Kentucky? If so, please contact us to schedule your assessment. Also, let us know in the comments below if you’d like to suggest a future blog post.

Perhaps you’d like to tackle your own crawl space repair. Visit our DIY Store.

Contact us if you need help fixing your crawl space or yard drainage by clicking here.

Learn about Crawl Space Ninja Franchise opportunities.

Why Did the Mold Come Back

The short answer to the questions of why mold disinfectant didn’t work and why mold came back is most likely that the proper sequence of treatment steps was not followed. If you don’t want to keep chasing the same dog, you can maximize mold treatment efforts by following the steps in this video and in the order described by Michael Church.

1. Install a dehumidifier and seal all but one of the foundation vents to lower humidity and wood moisture; install a continuously operating exhaust fan into the remaining vent.

2. Remove subfloor insulation and prepare the subfloor and joists for mold removal.

3. Monitor wood moisture content to keep it in the sweet spot between too high (which can grow mold) and too low (which can cause brittle wood members).

4. Install water management of at least a sump pump and possibly an interior French drain; for now, keep existing vapor barrier in place to keep the dehumidifier from also having to condition moisture coming up from the ground. Here in the NW Atlanta area, our rainy season is nearly year-round and our crawl spaces take on water not only from rain but from hydrostatic pressure of ground water seeping through the walls and floor.

5. Remove surface mold before applying product per EPA and manufacturer instructions; we remove surface mold by blasting it with sodium bicarbonate to get into nooks and crannies that are inaccessible otherwise. NOTE:  mold is microscopic, so if there’s enough growth to be seen, the surface mold needs to be removed so the product has any chance of getting to what cannot be seen.

6. Disinfect the wood after surface mold has been removed.

7. Apply a preservative and moisture preventative for longest-lasting results. Does your crawl space need a ninja? Give us a call today!

Lucie Woolery, Owner, Crawl Space Ninja of NW Atlanta/Smyrna GA

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