Risks of Fiberglass-Layered Insulation

About Fiberglass Insulation

• Fiberglass insulation is a material made from sand and recycled glass spun into glass fibers. Mineral oil and silicone are added to control the dust, and binders and dye create the fiberglass batts that are seen in home improvement stores. Though some of these components are toxic and may cause cancer, once properly installed and separated from common living spaces, it does not pose a risk to human health.

R-Value of Insulation Layers

• The most important feature of fiberglass insulation for homeowners to understand is the material's R-value. R-value is a measure of the material’s resistance to heat flow. This ability allows the material to prevent heated air from escaping to cold spaces of the house structure or to the outside air. How much R-value your home needs is determined by weather conditions, the type of heating and cooling system, and what part of the house is to be insulated. When determining the R-value of several layers of insulation, add the R-values of the individual layers together.

Risks of Fiberglass Insulation Layers

• Simply layering fiberglass insulation rolls or batts together is not the best method of insulating your home as fiberglass is not air-tight. Air penetrates through the materials. Some fiberglass insulation is laced with foil which traps air and moisture. When laying fiberglass insulation, you should place the faced surface toward the heated and cooled area of the home. If you are applying another layer of fiberglass insulation, it should be the unfaced type, without the foil backing. This unfaced layer can be installed on top of the faced layer to keep moisture from getting trapped between the two layers.

Precautions for Working With Fiberglass Insulation

• Because certain health problems can occur from working with fiberglass insulation layers, you should always wear protective clothing to keep the fiberglass materials off your skin, wear goggles to protect eyes from loose fibers, and wear a respiratory mask to prevent breathing in the fibers. Wash your hands after handling the materials and launder clothing that was in contact with the materials. Keep fiberglass insulation out of soffit vents and HVAC equipment.