Polystyrene, also known by the brand name Styrofoam, is a type of petroleum-based plastic made from a monomer called styrene. According to the Earth Resource Foundation, this lightweight material is actually about 95 percent air. It has excellent insulation properties and is used for products ranging from coolers and cups to home insulation. When installed properly, polystyrene insulation is an excellent way to reduce heat escape from a home. However, it does come with a few problems.
Environmental and Health Problems
Styrene production uses petroleum, a nonrenewable resource. According to the Earth Resource Foundation, polystyrene manufacture was also the fifth largest producer of hazardous waste in the 1980s and continues as a major polluter today. Polystyrene production also creates air pollution and poses a number of health hazards to workers, including eye, skin and respiratory irritation. Chronic exposure to styrene can cause central nervous system problems.
Polystyrene insulation in the form of small beads, meant for pouring into hollow wall cavities and concrete blocks, has a very high mobility. According to the US Department of Energy, it is extremely lightweight and acquires a static charge easily, making the beads hard to control. These beads may fly out of blocks or cavities when exposed to wind, may stick to surfaces when charged with static electricity and can pour out of crevices in a wall. Some builders mix these beads with concrete or other materials to keep them in place.
Polystyrene and other foam insulation products are often used where fiberglass batt insulation is undesirable due to a risk of mold. However, foam insulation in wet conditions, where organic debris are allowed to remain on the surface, may produce mold. Some of these mold species are dangerous to human health. Installers of polystyrene insulation should take care to prevent debris from accumulating and to maintain a dry environment around the foam. Moisture trapped between foam and exterior walls may also cause wood rot in nearby wooden objects.
Don't expose foam insulation to direct sunlight. Over time, polystyrene becomes damaged by UV rays, and loses its insulative properties. As the foam breaks down, it may also leach toxins into the air of the home. Coat exposed polystyrene insulation in rubberized paint, tar, silicone or acrylic, or use a plastic or rubber membrane. Check the compatibility of all coatings before using them on polystyrene insulation; some may dissolve the styrene plastic.
- Photo Credit concrete block wall image by Jim Mills from Fotolia.com