It’s March, spring is just around the corner and many individuals are in the spring cleaning mode.  One of the places you should not overlook is your crawl space.  Many of these crawl spaces are dirt and are located in the humid southeastern United States and do not have a crawl space dehumidifier or vapor barrier.  It is not uncommon in the southeast to see crawl space humidity levels at 50% to 90%.

For several decades, American homes have been built over dirt crawl spaces because it was simple and cheap.  Unfortunately, many of these dirt crawl spaces were vented based on the faulty assumption that these vents would allow moisture to escape from the crawl space.  In fact, many outdated state codes still require this.  We now know that these vents actually increase the relative humidity level.  The natural upward air movement draws air from the crawl space vents up into the living space of the home.  Did you know that up to 40% of the air you breathe in your home was once in the crawl space?

Vented dirt crawl spaces create a ticking time bomb of potential problems.  The bare soil contains high levels of humidity that natural airflow patterns move upwards into your home.  This is referred to as the "Stack Effect".  This means that not only are mold spores and allergens entering your living space, but that moisture is entering the entire floor framing system under the house, paving the way for damaging wood rot.  This can result in expensive structural repairs to girders, floor joists and sill plates.

The long-term solution to these problems is not to put band-aids on the symptoms, but to focus on eliminating the source(s) of moisture.  Immediately fix any groundwater, plumbing or other obvious leaks.  Make sure gutters and downspouts are clear and drain away from the foundation of the house.  Remember, the longer you ignore moisture problems in your crawl space, the more expensive the repairs will be.  You will have to find a contractor or qualified handyman to crawl under your house and replace boards amidst all the wiring, plumbing, duct work and bridging present in the crawl space.

To protect your home and your health you should put down a vapor barrier and install a crawl space dehumidifier.  Although there are certain steps to follow, you don’t necessarily need to be Bob Villa to install a vapor barrier and dehumidifier in your crawl space.  You’re biggest risk is doing nothing.