Basement Mold-What’s Lurking Down There?

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Basement Mold-What’s Lurking Down There?

One of the most asked question I get is, “Why do I get mold in my basement?”

There are usually two main reasons homeowners get mold in their basement:  One is a basement that has an overall relative humidity above 45%. The other is ground water intrusion/drainage issues.

Let’s start with the relative humidity: We advise our customers to keep the levels below 45% through the use of a good dehumidifier. Frequently, this is followed up with a great question:  “Do I need to run my basement dehumidifier all the time?” The answer is, “Yes.”  A good quality dehumidifier, like the Santé Fe Classic, (see our blog on dehumidifiers: http://compmold.blogspot.com/2013/09/dehumidifiers-considerations-when.html) can be set to a 45% relative humidity level on the unit. Once the humidity level is set, the unit will shut off when it doesn't need to run. When you don’t run a dehumidifier in your basement on a regular basis, it allows all of your belongings in the basement to take on that moisture. With the lack of air flow and the high moisture content in them, you will start to get a musty smell and mold growth on these items.  It’s also important to have a large enough dehumidifier in the basement to accommodate the space and the amount of belongings you have.  At Comprehensive Mold Management, we can determine the correct size dehumidifier for your basement to help keep it dry and at the perfect levels.

The second leading problem is the lack of good drainage around the foundation of the house. Ineffective drain tile, the lack of a sump pump and/or drain tile, clogged gutters, or the negative pitch of the soil to the foundation are just a few issues. Using the proper coatings on the block walls is just as important. They should be guaranteed mold-proof. Mold needs two things to grow: a food source and moisture. If the wrong type of coating is on the block walls and there is poor drainage, mold will grow on the block walls. This is due to the fact that the improper paint becomes a food source for the mold, which is brought on by the excessive moisture behind it in your walls or floor. You may also incur peeling paint due to the product being applied onto the wet walls. The drainage issues should always be addressed before mold-proof coatings are applied.

We, at Comprehensive Mold Management, also advise limiting the amount of belongings being stored in your basement. Limited airflow may occur, making it much more difficult to remove moisture. In addition, if they already have mold on them, it can raise mold levels to a much higher rate.

You should also be advised that, if those existing mold spores in your basement are disturbed (ie: moving boxes, attempting to clean the mold yourself) without proper containment & negative air being run, you risk cross-contaminating your entire home, via your furnace, air conditioning unit or just by walking those items or moldy boxes up your stairs for disposal. It is always better to ere on the side of caution and call a mold expert to evaluate your basement before moving or cleaning anything.


Having proper dehumidification, water drainage & limiting stored belongings in your home is the key to keeping mold out of your basement area and off your valuables. Preventative measures go a long way in keeping your home’s environment safe and healthy.


Basement mold-Before
Basement Mold-After
Visit Comprehensive Mold Management's website for more information at www.compmold.com