12 MOST COMMONLY ASKED QUESTIONS ABOUT HOME INSULATION

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Kathleen Stewart
6 years ago
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1 12 MOST COMMONLY ASKED QUESTIONS ABOUT HOME INSULATION

2 Are there health concerns with fiber glass insulation or cellulose insulation? Is cellulose insulation or fiber glass insulation better at preventing air infiltration? The cellulose industry has yet to spend a dime on medical or health studies. Yet, wood dust has been linked to cancers of the upper respiratory tract and certain nasal cancers. Also, paper has dyes, inks and impurities within it that are questionable from a health standpoint. In addition, boric acid, borax, sulfuric acid, ammonium sulfate and calcium carbonate (often used to treat cellulose insulation for fire retardancy) are all considered toxic materials at certain exposure levels and they pose health risks over time, including nasal irritation, fever, weight loss, vomiting, diarrhea, skin rash, convulsions and anemia. Cellulose manufacturers often say that their insulation, when spray-applied, makes homes more air tight, resisting air infiltration. And yet no matter how well insulated a home may be, there will always be air infiltration around doors, windows and vents. Thermal insulation is not installed to prevent air infiltration. Proper caulking, sealing and the use of exterior wraps will. Fiber glass is one of the most thoroughly tested and researched products made by man. Over the years, the industry has spent tens of millions of dollars in medical and health-related research. This includes a number of animal, human and environmental studies. All these have shown no direct link between fiber glass and cancer. Properly installed fiber glass insulation will perform equally with cellulose as it relates to air infiltration. Again, caulking, sealing and the use of exterior wraps should be used to combat air infiltration.

3 Will fiber glass insulation or cellulose insulation absorb moisture? Is cellulose insulation or fiber glass insulation corrosive to pipes, wires and other metals? Cellulose insulation, because it is made of ground up newspapers, readily absorbs moisture. If wet, it can take a long time to dry. This can cause problems because, for cellulose to perform to its R-Value, the material must be dry. Also, wet cellulose usually compresses, which can severely affect its R-Value. Assuming existing cellulose does dry after becoming wet, there is a concern that the fire retardant chemicals can wash away, leaving an unsafe insulation material behind. Cellulose insulation, because of the same chemicals used to make it fire-retardant (particularly sulfates), can cause the corrosion of pipes and wires. There has even been a documented case where the fire retardant chemicals used in cellulose insulation have caused metal roof trusses to corrode and collapse. While it is not good for any insulation to get wet, fiber glass insulation does not absorb moisture. When dry, it will regain it's original R-Value. Fiber glass insulation is noncorrosive to pipes and wires. It does not contain any corrosive flameretardant chemicals that can corrode metals when it comes into contact with them.

4 Does weight have anything to do with choosing insulation? In a home fire, can either cellulose insulation or fiber glass insulation contribute to its spread? Cellulose insulation (even the so-called light density type), weighs more than fiber glass insulation. So, if a builder wishes to use cellulose for attic insulation above R-30, a traditional 1/2" ceiling drywall, 24" on center, should not be used. Fiber glass insulation is light weight, yet extremely thermally efficient. It can be installed to thicknesses greater than those recommended in today's CABO Model Energy Code with no threat whatsoever to the ceiling construction of a home or without requiring any changes to construction details. Cellulose insulation is made of ground-up newspapers: even though it has fire retardant chemicals in it, it will burn with a prolonged exposure to the heat of a fire (at as low as 450 F). Once ignited, the spread of fire from one end of an attic to another is very possible. Unfaced fiber glass insulation is noncombustible and therefore does not contribute to the spread of fire. If it comes in contact with the prolonged heat of a fire above 1200 F, it will simply melt. If using kraft or foil-faced insulation, while the fiber glass itself is noncombustible, the facing attached is flammable and should not be left exposed.

5 Is there a fire safety concern with fiber glass insulation or cellulose insulation? wood-framed walls. However, the facing or vapor retarder on kraft-faced or standard foil-faced fiber glass insulation is flammable and should not be left exposed. When correctly installed, it does not pose a fire hazard. Cellulose insulation, made from ground-up newspapers, is naturally flammable and must be treated with chemicals like borax, boric acid, sulfuric acid, ammonium sulfate, aluminum sulfate and calcium carbonate, in order to meet fire safety requirements. Doubts have been raised concerning the permanency of the fire resistance of cellulose. For example, after some attic fires in California, the California Bureau of Home Furnishings and Thermal Insulations conducted a series of tests with cellulose. The Bureau analyzed the material to determine the effect of aging on its flame resistance. The results of the third year of testing show that flame spread resistance has declined to levels below what is required for new material. In addition to questions about the flame resistance of cellulose, there is also a concern about smoldering and reignition problems with this type of insulation, should a fire start. Fiber glass insulation is permanently noncombustible. It does not have to be treated with fire-retardant chemicals. Unfaced fiber glass insulation is, in fact, recognized by building code groups as an acceptable fire stop in residential With concerns for the environment so great today, do cellulose and fiber glass insulation manufacturers make any environmental contributions, like recycling? Cellulose is composed of 80% recycled (ground-up) newspapers and 20% fire retardant materials. The percent of recycled material (glass) in fiber glass varies by the plant in which it is produced. Currently CertainTeed is using an average of 20% recycled glass and plans to increase that percentage.

6 Does fiber glass insulation or cellulose insulation settle after installation? Which insulation offers the highest R-Value per inch? Most cellulose manufacturers agree that cellulose insulation settles by approximately 20% from its installed thickness. If cellulose is installed to the thickness stated on most bags, it will lose about 20% of its R-Value when it settles. Currently, efforts are being made to require cellulose manufacturers to state both initial installed and settled thicknesses on their product packages in an attempt to ensure that contractors install enough product to give homeowners the R-Value desired. Settling is not a factor in the thermal performance of fiber glass insulation. Fiber glass batts and rolls do not settle. Fiber glass loose-fill settles very slightly over time, usually 1% or less. All in all, fiber glass insulation, when installed correctly, maintains its thermal performance for the life of the dwelling. High-density cellulose insulations offer higher R-Values in the range of R-3.0 to R-3.7 per inch. However, R-Value per inch is really only an advantage if the area being insulated is only inches deep. Standard fiber glass batts and rolls offer an R-Value of approximately 3.0 per inch. InsulSafe 4 Blown-In achieves an R-Value of 2.4 per inch in open blow applications, but an R of 4.0 per inch in sidewalls, which is greater than cellulose. In addition, CertainTeed's new highperformance fiber glass insulations are manufactured to provide higher R-Values per inch than cellulose and standard fiber glass insulation.

7 How do cellulose insulation and blown-in fiber glass insulations compare in regard to dust? Does convection cause a problem with either cellulose or fiber glass insulation? Cellulose insulation creates very visible, annoying levels of dust, according to those who install the material. The dust is so fine that common disposable dust respirators may not be acceptable to use when installing or handling cellulose. Blown cellulose is far dustier than blown-in fiber glass insulation. Some fiber glass dust is contained in fiber glass insulation. However, OSHA considers this nuisance dust. Therefore, CertainTeed requires people handling and installing fiber glass insulation to wear common disposable dust respirators. Information on this is printed on each package of CertainTeed. CertainTeed's InsulSafe 4 Blown-In Fiber Glass Insulation is considered by many installers to be the least dusty of all blown-in insulation products on the market today. Convection has little if any effect on the thermal performance of cellulose. Fiber glass batts and rolls also are not affected by convection. Loose-fill fiber glass is affected, but the results are minimal. It has been calculated that the loss of R-Value, even in the very coldest parts of the country, results in less than $20 per year in increased gas costs. This loss only begins to occur if the attic temperature falls below about 0º F.

8 CertainTeed Home Institute P.O. Box 860, Valley Forge, PA Web Site: CertainTeed Corporation 6/01

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