The following conditions are necessary for mold growth to occur on surfaces:

• temperature range above 40°F and below 100°F
• mold spores
• nutrient base (most surfaces contain nutrients)
• moisture

Human comfort constraints limit the use of temperature control. Spores are almost always present in outdoor and indoor air, and almost all commonly used construction materials and furnishings can provide nutrients to support mold growth. Dirt on surfaces provides additional nutrients. Cleaning and disinfecting with nonpolluting cleaners and anti microbial agents provides protection against mold growth. Other sections of this document have discussed the importance of building maintenance and proper sanitation in preventing IAQ problems. However, it is virtually impossible to eliminate all nutrients. Moisture control is thus an important strategy for reducing mold growth.

Mold growth does not require the presence of standing water; it can occur when high relative humidity or the hygroscopic properties (the tendency to absorb and retain moisture) of building surfaces allow sufficient moisture to accumulate. Relative humidity and the factors that govern it are often misunderstood. This appendix is intended to give building managers an understanding of the factors that govern relative humidity, and to describe common moisture problems and their solutions.

Background on Relative Humidity, Vapor Pressure, and Condensation

Water enters buildings both as a liquid and as a gas (water vapor). Water, in its liquid form, is introduced intentionally in bathrooms, kitchens, and laundries and accidentally by way of leaks and spills. Some of that water evaporates and joins the water vapor that is exhaled by building occupants as they breathe or it is introduced by humidifiers. Water vapor also moves in and out of the building as part of the air that is mechanically introduced or that is infiltrated and exfiltrated through openings in the building shell. A lesser amount of water vapor diffuses into and out of the building through the building materials themselves.

Can Mold Make Me Sick?

Yes, mold can make you sick. In addition to its being an unpleasant odor and sight, mold can cause harmful effects to human health that might turn to allergic infections and toxic reactions.

The most common Allergic Effects are:

• Nasal congestions and irritation
• Mucous membrane irritation
• Allergic reactions – Rhinitis and Asthma
• Sneezing and coughing
• Throat and eye irritation
• Difficulty breathing
• Asthmatic attacks
• Itching and skin stains.

Infectious Effects
Immune suppressed patients are more likely to develop mold infections. Included in such groups we can highlight the danger to patients who are:

• HIV positive
• Organ transplant patients
• Burned
• Under chemotherapy or radiotherapy
• Newborns
• Elderly
• Other immune-suppressed patients

Toxic Effects
Mold toxins studies suggest that toxins may be the cause of:

• Pulmonary hemorrhaging
• Reactions in the immunological system (reducing the ability of the organism to react to diseases)
• Neurotoxin effects such as fatigue, headaches, memory loss, depression, erratic moods, convulsions and shaking
• Potential cancer trigger

How Do We Help You Control Mold?

We install vapor barriers, foundation vents, crawl space humidistat fans, and dehumidifiers.

• The key to mold control is moisture control.
• If mold is a problem in your home, you should clean up the mold promptly and fix the water problem.
• It is important to dry water-damaged areas and items within 24-48 hours to prevent mold growth.

For more information on Mold & Moisture control, please visit the EPA.
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