Moisture, Mold and How to Control It

Too much moisture in a home or building can lead to a number of problems, some of them being quite serious. Increased humidity levels inside the home or building can produce an uncomfortable sensation of dampness and cause wood to swell and warp (or even rot), causing a weakened home or structure.

Too much moisture can also allow mold to grow. Mold, in turn, can cause the musty odor associated with mold contamination, can discolor and damage homes and buildings, and even cause health problems. According to the U.S. Environmental Protection Agency, the best way to control mold growth is to control moisture.

Many Sources of Moisture Intrusion in the Home

Dampness by window, indoor water leaks, broken pipes, water leaking from a clogged air conditioner drain pipe, a leaky roof, poorly sealed windows, basement flooding, steam from showers or cooking – these are some common conditions that allow moisture to become a problem in homes, apartments, schools, and the workplace.

Outside Sources

There are many other conditions that can contribute to water intrusion and lead to mold proliferation, for instance gutter downspouts or lawn sprinklers placed too close to an outside wall. They can cause water to seep straight into a basement or saturate a concrete foundation. Once the concrete becomes wet, moisture can wick into the home or building.
Construction Issues

Also, using polyethylene PVC piping instead of copper or galvanized piping (the PVC pipes can be punctured easily by nails or staples), improperly sealed bathtub drains, improperly sealed sinks and garbage disposals, or even the installation of particle board after it has been rained on during construction – all of these issues can cause mold growth.

Water Vapor

When relative humidity indoors increases to 60 percent or more, building materials and furnishings absorb the moisture. These damp materials are a good source for mold to grow. If the relative humidity remains high (above 60 percent) for an extended period of time, mold almost certainly will grow.

Seasonal Changes

Heated air can trigger moisture problems because it holds more moisture than cool air. Consider what happens in the fall or winter. The warm indoor air comes in contact with a cold surface (single-pane windows or non-insulated walls). The air then cools down and excess moisture condenses. That moisture can lead to mold and mildew.

Damp Concrete

Wet or damp concrete slabs often contribute to indoor mold problems. Concrete absorbs water like a sponge. That, in itself, is not a problem. However, anything attached to wet concrete, such as wood flooring, carpet, cabinets, wood framing, and so on, can all absorb the moisture from a concrete slab. These materials then become ideal food sources for mold.

Concrete can get wet in any one of several ways. The lack of a good moisture barrier under poured concrete slabs can be a problem because moisture can wick up into the concrete from the ground that’s damp or wet because of improper irrigation or drainage. This is sometimes a problem in California where the land slopes toward structures, enabling rain and irrigation water to flow to the slab, where it becomes saturated.

In some cases, the concrete may never have dried after being poured. Contractors who are under pressure to meet completion deadlines may not allow the concrete sufficient drying time before beginning construction. That means the slab stays wet for months, even years longer than it should, never really drying out.

Whenever there’s a water or moisture problem, it’s not long before there’s also a mold problem. That’s because mold grows quickly under wet or damp conditions.

“Molds can cover large areas within 24 to 72 hours after water damage occurs,” says Dr. Luke Curtis, a medical doctor and Certified Industrial Hygienist. Dr. Curtis has assessed more than 1,000 buildings for mold and moisture problems as well as other issues of indoor air quality.

What is Mold?

Mold SporesMolds are fungi that thrive everywhere – both indoors and outdoors. They grow best in warm, damp, and humid conditions. When conditions are right, mold can even grow in areas where humidity is low, such as Arizona.

Molds reproduce by forming spores that are spread by air currents. Since mold spores are literally everywhere, there is no reliable and cost-effective means of eliminating them from human environments or creating a mold-free space. We can, however, limit mold growth by controlling the amount of moisture in our indoor environment.

Mold needs four things to grow:

Mold spores
Nutrients – any organic substance such as wood, paper, drywall
Moisture – water, condensation, or damp air (when the humidity
is above 60%)
Appropriate temperatures – between 40 and 100 degrees

No one knows how many molds or species of fungi exist. Some estimates range from tens of thousands to upwards of 400,000, although less than 100,000 have been named.

There are approximately 1,000 types of mold found indoors across America. Less than 80 molds are suspected of causing some form of illness, and only a handful are considered toxic.

The common types of mold found indoors includes:

Aspergillus and its subspecies
Stachybotrys atra, also known as “black mold”

Mold often grows in places not readily visible. It can be found behind wallpaper or paneling, the topside of ceiling tiles, the back side of drywall, or the underside of carpets, carpet padding, or wood flooring. Piping inside the walls may also be a source of mold growth since pipes often leak and cause moisture and condensation. Roofs, too, sometimes leak and water collects inside walls and insulation.

Mold spores, whether dead or alive, can also cause a number of adverse health problems in humans, especially those who are sensitive to molds. Symptoms include nasal stuffiness, eye irritation, wheezing, or skin irritation. Those people with serious allergies to molds may experience fever or shortness of breath. Persons with chronic lung illnesses, such as obstructive lung disease, may develop mold infections in their lungs.

Assessing a Mold Problem

If there is only minor surface mold, usually the home or building owner doesn’t need to call in an expert, but if the mold is widespread, has caused visible damage, and is suspected of causing health problems, it’s best to call a professional who is certified and trained in dealing with mold.

Professional Assessing Mold Certified professionals, like those at Holt Construction Group, are trained in mold assessment and mold remediation and belong to IICRC (Institute of Inspection, Cleaning and Restoration Certification). Another type of trained professional who also assesses and remediates mold is the Certified Industrial Hygienist. A CIH member typically belongs to the American Board of Industrial Hygiene (ABIH) or the American Industrial Hygiene Association (AIHA).

It’s important that people with mold problems hire someone who is trained in mold identification and remediation. Mold assessment and identification presents many challenges and can easily be done improperly by untrained persons. For instance, in the aftermath of Hurricanes Sandy, Irene, Rita, and Katrina, many companies sprang up claiming to understand the issues of mold contamination. Yet they failed to follow proper protocol and, as a result, many home and business owners lost both their properties and money to these unscrupulous firms.

Mold specialists can approach a mold situation in one of two ways. By state law, they can either do a mold assessment or mold remediation. They cannot do both, since to do so would be a conflict of interest.

A mold assessment determines if mold is present. This is done by visually examining the premises and testing.

Moisture present behind walls or beneath floors can be detected with a sensitive infrared camera which produces a vivid temperature map of wet areas. The temperature difference created by the presence of moisture on the inside surface of a wall will appear differently than the surrounding area. In other words, materials that retain moisture are cooler than things that are dry.

Although infrared inspection is a fast, non-invasive method to discover moisture intrusion within a home or building, it does not directly detect the presence of mold. Instead, it’s used to find moisture where mold may develop.
Moisture Meters Indicate Level of Moisture

Indoor temperature and relative humidity tests are run throughout the premises, checking for unusual differences between rooms. Indoor relative humidity should be between 40 and 60 percent. Anything higher can lead to mold.

When there are hard-to-reach areas to examine, such as cavities in ceilings, walls, and floors, Certified Industrial Hygienist Dr. Curtis sometimes employs fiber optic devices to detect moisture. Some fiber optic devices carry light into confined spaces, while others have a video capability that allows the user to see close up what he cannot easily access.

Corrective action may be simply sanitizing and fogging the premise with a biocide to kill the mold and its spores, or it may require moderate to extensive mold remediation.

Mold Remediation

Mold remediation is simply a professional term for mold removal. If remediation is necessary, the assessment details what is required to remove it.

It’s up to the client to follow through on the assessment. He can plan to do some of the work himself (e.g., tear out a wall) or hire a mold remediation specialist to handle everything carefully and keep the contamination to a minimum.

The client also has to decide who does the build back. For instance, if a wall is opened up, the client has to decide whether the remediation specialist repairs the wall, or someone else does the work.

What happens is you’ll kill the mold but you’ll leave the carcass behind. The carcass will disintegrate and can cause toxins to be released into the air. So you really went from one problem (mold growth) to another problem.

Another thing to keep in mind is that bleach only kills the mold spores are on the surface of wood or other organic material. The mold, however, tends to grow and establish roots below the surface and into the organic material. Due to the chemical makeup of bleach, it does not absorb into wood or other materials. Then, once moisture is reintroduced in the environment, the mold will grow right back.

Build Back

Once the mold is eliminated, the source of its growth (e.g., broken water pipe) corrected, and the affected areas removed (e.g., portions of a wall damaged by mold), the final step is the build back. Here the client can decide to have the mold remediation specialist do the repairs, hire someone else, or even do the repairs himself.

In Closing

Mold is everywhere. There’s no escaping it, but we can keep it from becoming a problem by eliminating moisture and excess humidity from indoor environments.

When mold does appear, it can not only damage property but cause adverse health effects as well. That’s when it’s best to hire a trained and certified mold specialist. He has the knowledge and the proper tools to find, identify, and eliminate the problem.