Mold and Mildew

Mold has become a big issue in recent years -- the subject of lawsuits, closed schools, and the impedus for the growth of a "new" industry, mold testing and remediation. Discover how mold affects your indoor air quality and your health.

With all this talk about mold, you might think it is new. It is not new. You might think it is a complex issue. It is not a complex issue, but rather very simple. First, let's talk about why mold is here in the first place. Mold has a purpose. Its purpose is to breakdown, or eat, dead organic matter. Without mold, plant and animal material would grow and grow and pile up and pile up.

Mold Intelligence
Mold knows why it was put here. If it's organic, dead, and wet, mold knows to eat it. Organic means it is a material that was once living, such as wood. Mold sends out its spores everywhere, which can lay dormant for many years. So when something is organic, dead and wet, mold grows on it and eats it. When we say "mold", we mean any mold or other fungi, of which there are many thousands of varieties.

Since mold spores are everywhere, and our building materials and contents of our homes (furniture, boxes, clothes, etc.) are made from organic materials, this factor cannot be controlled. The only one that we can control in our homes is the moisture.

Mold needs 70% Relative Humidity (RH) to grow; however this is a loose number. Some molds can grow at less RH.  In many cases, like in a crawl space, the RH of the surrounding air, and the RH of the surfaces are two different things because of temperature differences between air and surfaces.

Mold Growth and Mold Food
Mold likes processed organic fibers best. In other words it will grow on paper and cardboard first. Paper is like "mold candy". After that it will grow on fiberboard and chipboard, and then plywood, and finally on framing lumber. Sheetrock has paper on it. Mold loves sheetrock.

Mold Allergies and Health
Mold releases airborne spores or "seeds", which are so light they float on the slightest air currents, off to find more suitable places to grow. Most people are not allergic to mold spores, but some are. The higher the concentration of mold spores, the greater percentage of people who will be bothered by them.

There is plenty of information out there on the health effects of mold, and they will not be explained here. One thing is for sure, mold growing in your house is not good. It's not good for your health, and it is increasingly not good for your property value. Who wants to buy a house with mold? Nobody.

Structural Damage to Your Crawl Space
There is another industry that has vented dirt crawl spaces to thank for its existence Structural repairs to replace floor joists, girders, and sill plates basically the entire floor framing system under your house. These repairs aren't cheap. In fact, they can be very expensive. You can imagine a carpenter figuring out how he's going to crawl under your home and get new 16 foot long 2" x 10"s in place, with all the duct work, wiring, plumbing, and bridging (cross bracing) that are attached to the old rotted joists, all while operating on his back in a low crawl space. It's not easy on him, and it's not going to be easy on your bank account.

Most of the time, these structural repairs are done without ever fixing the problem! So it's only a matter of time before the new framing rots out, and it has to be done again.

What is the design life of a house? In other words, how long do you want your house to last without needing major repairs? If the answer is longer than 10 or 15 or 25 years, then you better fix your dirt crawl space.

Mold Rotted Floor Joists
When the floors in nearly all 36 units in this New England condominium complex began bouncing and getting soft, they realized the crawl spaces were a bigger problem than they thought. As an emergency measure, they had to "sister" new framing lumber to each side of every girder and every floor joist so the homes would not cave in. Eventually they hired Basement Systems to install a CleanSpace Crawl Space Encapsulation system to fix the moisture problem.

Rotted Sill Plate
The sill plate rotting right over this vent is no coincidence. That the problem wasn't fixed after it was replaced is the irony.

The Solution
There are three things that destroy organic materials in general, and wood in particular: water, heat and ultra-violet radiation. Of these, water is by far the most important.

Water leaks, moisture, or high humidity levels in a home are a very bad idea. And water vapor moves easily upwards into the house environment. A damp environment is very unhealthy and destructive. Mold thrives and reproduces by producing airborne spores by the millions, and some molds are toxic. Insects and critters of all kinds love damp environments and wet materials. Rot and decay occur in damp environments causing structural damage.

The natural airflow in a house is from bottom to top. This sucks the moist air and everything in it up into the living areas of the home.

Mold spores, odors, humidity and critters create a very unhealthy environment for people. Many people are allergic to these things, and experience a host of symptoms and don't realize that their dirt crawl space is affecting their health.

By stopping water leaks and removing humidity from the air these things can be prevented.