Moisture and mold, and their relationship to building materials

Frequently asked questions on these subjects, along with some straight answers that contractors can pass along to their customers!

Why am I suddenly hearing so much about mold and mildew?
There has been a heightened focus on this subject in the media, largely due to some high-profile litigation related to mold buildup and remediation. It has certainly brought more focused attention on builders and trades, who are being asked to more carefully watch for ways to prevent moisture from entering the building envelope. Mold cannot grow without the presence of moisture on a receptive surface, which is the true-yet preventable-culprit in this equation.

What are the most common sources of moisture on the job site?
Sources of moisture typically include moisture levels in the lumber, wet building materials, leaks in the building envelope itself or its plumbing system, HVAC condensation, window condensation or even minor flooding.

When is moisture most likely to enter the building?
The great majority of moisture problems occur during the actual construction phase, when materials are delivered and installed. Also, an accelerated construction schedule can force the contractor to begin installing materials before the envelope has been properly protected from moisture and the elements. Faulty HVAC systems and improper design are two other common sources of moisture.

Do most building materials support the growth of mold and mildew?
Mold and mildew grow in or on virtually every construction or building material currently in use. Given the right conditions, almost any material can be overwhelmed by mold; even aluminum, steel and glass will support mold growth under the right conditions.

What conditions are necessary for mold to grow?
Moisture, mold spores, a food source and a receptive surface to grow. Since spores waft about nearly constantly and building materials (the food source) routinely contain over 19% moisture, not to mention humidity and condensation, the playing field is set.

Can mold affect your health?
The vast majority of molds are not harmful to healthy individuals; in fact, many varieties of molds are healthy in nature. However, excessive exposure to certain molds may cause or worsen conditions such as asthma, hay fever or other allergies.

Is there a simple, "common sense" approach to avoiding mold growth?
Control the moisture and receptive surfaces that can result in mold formation. This requires careful design, proper construction techniques and thorough inspections and maintenance throughout the life span of a building. This means that architects, designers, contractors and maintenance engineers must work more closely together than ever.

What about using "moisture resistant" building materials?
Some manufacturers have products that will resist moisture and mold growth. However, one must realize that moisture is not simply a product issue, but a building systems issue. As such, moisture control must be viewed in the same way issues such as fire resistance, sound control, abuse resistance and aesthetics are addressed. Products alone will not mitigate any major problem.

What is the best way to tell if there is a mold problem?
Contact a local building inspector and ask about their mold testing and remediation services. They can be of help in assessing your problem and either providing a remedy or recommending someone who can clean it up.