Why Does a House Get Mold?

Article by David Selter

Well, we do a lot of mold testing, and we can tell you that mold in a home is not the sign of a dirty house. It’s just that the conditions that are ideal for humans to live in, are also ideal for mold to live in.

The wood and drywall used in the construction of your home is an almost unlimited source of food for mold, and the temperature range that people typically keep their home in is also the ideal temperature range temperature for the growth of mold. And if that wasn’t enough, the tiny lightweight mold spores, by which mold reproduces, are always in the air, especially in our gulf coast climate.

So maybe the real question is – why doesn’t every home need mold remediation? It turns out that the deciding factor is moisture. Without it, mold can’t grow. And moisture is the one thing we can control. We can’t live outside of a pretty narrow temperature range. We can’t live without being protected from the elements by building materials. And we can’t magically eliminate all mold spores from the air. But we CAN control the moisture in our homes.

So where does the moisture that leads to a moldy home come from?

One common source of moisture is excessive humidity in the house. When the humidity in a house is too high, some of that moisture condenses on the walls. That moisture, along with the dust in the air, provides a perfect environment for the mold spores in the air alight and begin to reproduce.

You might have seen this occur on your AC vents if they tend to always be sweating when the AC is running. The EPA says that indoor humidity above 60%: “can supply enough moisture for mold growth”. They continue: “Indoor relative humidity (RH) should be kept below 60 percent — ideally between 30 percent and 50 percent”. Usually, the AC system is the culprit when the humidity in your home is too high.

Other sources of unwanted moisture that commonly cause mold problems are slow leaks in drain pipes and water supply lines, groundwater seeping in from outside, especially after rainstorms, and water intrusion from roofing issues including deteriorating roof flashing and backed-up gutters.

So be on the lookout for signs of moisture, such as water stains on drywall and musty smells. If you prevent unwanted moisture in your home, you will prevent the growth of mold.