The STACK EFFECT

Does your home smell musty or earthy, especially in the summer? Ever wonder where that smell is coming from? Well, wonder no more because of the “Stack Effect” those smells and off odors come from your crawl space or basement and indicate that your home is suffering from indoor air pollution.

The “stack effect” is when warm air moves upward in a building. This happens in summer and winter, but is most pronounced in the winter because indoor-outdoor temperature differences are the greatest. Warm air rises because it’s lighter than cold air. So when indoor air is warmer than the outdoor air, it escapes out of the upper levels of the building, through open windows, ventilation openings, or penetrations and cracks in the building envelope. The rising warm air reduces the pressure in the base of the building, forcing cold air to infiltrate through open doors, windows, or other openings. The stack effect basically causes air infiltration on the lower portion of a building and exfiltration on the upper part. Mechanical equipment such as fans and blowers causes the movement of air within buildings and through enclosures, which can generate pressure differences. If more air is exhausted from a building than is supplied, a net negative pressure is generated, which can induce unwanted airflow through the building envelope. Bathroom exhaust fans, clothes dryers, built-in vacuum cleaners, dust collection systems, and range hoods all exhaust air from a building. This creates a negative pressure inside the building. If the enclosure is airtight or the exhaust flow rate high, large negative pressures can be generated.

Where does most of that air come from? … you guessed it … the crawl space with all the pollutants … keep reading.

Anybody in your family suffering from allergies, unexplained headaches, asthma or asthma like symptoms? Indoor air pollution has been listed as the #1 health problem by the EPA  with indoor air being up to 100 times more polluted that outside air.

Indoor air pollution consists of 3 main pollutants.

1) Particulates – these are tiny microscopic particles suspended in the air and can include dust mites, dust mite excrement, pollen, smoke, dust and fiber glass particles if fiber glass batt insulation is present.

2) Microbial pollutants include mold, mold spores, bacteria, fungi, viruses, and other organisms that thrive in the damp, humid environment of the crawl space.

3) Gases are the third type of air pollutant that migrate upwards into the living space. These are the cause of the odors and strange smells that comes from the crawl space. Additionally, bacteria and organics in the soil can react giving off odors, and when covered by a vapor barrier, depriving the bacteria of oxygen, can produce a cat-urine odor that is unbearable.

At CCSS we’ve already found the solution to poor indoor air quality thus preventing family suffering with allergies and respiratory problems.

Call (704) 989-8219 for your FREE crawl space evaluation.