My Polystyrene Insulation Board Is Leaking

Types

• Several types of polystyrene insulation boards are used in residential homes. Beadboard is one type of polystyrene insulation that typically absorbs moisture and is susceptible to damage from water leaks. Roof insulation materials and wall insulation are often constructed from polystyrene beadboard. Extruded expanded polystyrene foam board is a closed-cell foam insulation that is often used because of its strength. This type of polystyrene foam insulation is more resistant to moisture damage than beadboard but may develop damage if water leaks for extended periods of time. If your insulation becomes damaged, air may also leak into your home, making it less efficient.

Causes

• Uncontrolled water leaks inside your home's structure will eventually damage your insulation. Missing or damaged shingles may cause your roof to leak, allowing water to run down into the walls and cause damage. Poor lot drainage will also allow water to enter through the cracks in the foundation, causing the insulation to become wet. Water vapor moving through your home may also cause the insulation to become moist. Once polystyrene foam board insulation is wet, it will begin to deteriorate and allow air to leak inside your home.

Effects

• When polystyrene foam board insulation becomes saturated with moisture, it holds water inside the foam cells. Eventually, mold will begin to grow on your foam board insulation. Mold growth will damage the structure of your home, making costly repairs necessary. People who live in homes with mold growth often develop health problems such as nasal congestion, sneezing, wheezing and itching eyes. Those who have respiratory conditions such as chronic obstructive pulmonary disease or asthma may suffer an increase in symptom severity when exposed to mold each day.

Solutions

• Locating and repairing all water leaks is key to preventing moisture damage and mold growth. Once you have all leaks repaired, replace the damaged portion of the polystyrene insulation. Scrub any mold around the area away using liquid dish detergent and water. When all visible mold is gone, rinse the area and dry thoroughly. Depending on the climate you live in, installing a vapor barrier on the warmest side of the wall cavity may reduce condensation, according to the United States Department of Energy. Check your local building codes to determine if you are required to add a vapor barrier. Inspect your home for other signs of insulation damage that can cause air to leak inside your home. Seal all gaps or cracks with caulk to keep air movement to a minimum.