Cellulose insulation is manufactured from material prepared from natural wood based fibers and treated chemically so that it meets federal standards from flame resistance and the ability to resist corrosion. Generally, recycled newspapers constitute the basic raw material for cellulose insulation.
Is Cellulose a New Material?
Although many people are only beginning to learn about the advantages of cellulose, this form of Insulation is not new. In fact, cellulose is one of the earliest forms of residential insulation in the United States. With the availability of inexpensive energy very little insulation of any type was used until the 1930s and 1940s, and only then to make electric heat economically viable. Early promotion by the electric utilities fostered the use of cellulose insulation, which was the only type efficient enough to permit the early use of electric heat.
What Are the Most Common Applications of Cellulose?
Cellulose can be installed easily in most parts of the house. The main sites are the attic floors, basement ceilings, crawl spaces and side walls.
1. ATTICS The ease with which cellulose can be installed makes it a prime candidate for retrofit attics. Cellulose loose fill can be blown in which it easy to install from the sides to reach all areas. In an attic, cellulose compares more favorably with fiberglass and rock wool because of its higher R-value. When fiberglass loose fill materials are installed, there can be a problem with “fluffing.” Contractors have been known to fluff the insulation so that it appears to have added thickness. For the homeowner, “fluffed” fiberglass means lower R-value protection than expected.
2. BASEMENT CEILINGS Cellulose has begun to be used recently in insulating floor joists in unheated basements. A new system uses a semi-rigid plastic material fastened to the underside of the floor joists. The cavity in between is blown with cellulose.
3. SIDE WALLS Cellulose can be used in old un-insulated walls by drilling the wall, blowing in the cellulose and then plugging up the hole. In new construction, cellulose can be installed in the same manner to get a higher R-value than would be achieved by mineral fiber batts. Another method for installing cellulose into new walls is to use specially manufactured cellulose which contains a dry adhesive. This material can then be sprayed into the wall cavity with a light water mist which activates the adhesive and holds the cellulose in place. With properly applied spray cellulose, dry wall can be installed within 2 days.
What Are the Benefits of Using Cellulose? Is Cellulose an Effective Insulation?
There are two types of insulation to choose from: cellulose or Insulation made from mineral fiber or mineral wool, such as fiberglass and rock wool. Cellulose has these advantages:
1. THERMAL EFFECTIVENESS Thermal effectiveness is measured in R-values. The “R” stands for resistance to the flow of heat. The R-value of any material is a measure of how good an Insulator it is, that is, how well it resists the flow of heat into a home in summer or out of it in winter. The higher the R-value, the more the material resists the flow of heat. Cellulose Insulation has a higher R-value than that of fiberglass or rock wool. The nominal R-value per inch of cellulose is 3.
2. AIR INFILTRATION RESISTANCE Studies have shown that more than 30% of average home heating cost is to combat air infiltration through the wall. Natural cellulose fibers, blown-in between walls effectively seal all air gaps and creates a barrier against air convection. Conventional insulation batts cannot completely fill cavities. This allows air to circulate inside the walls, bringing cold air in direct contract with the interior wall. The inside wall is cooled which, in turn, cools household air near. The cooled air then drops to the floor starting an uncomfortable air convection flow. Cellulose prevents this and results in lower heating costs and a comfortable draft free home.
3. FREE OF HEALTH CONCERNS Unlike fiberglass, cellulose insulation does not contain glass fibers and there is not itching or scratching of the skin during installation. Also, unlike fiberglass, which carries a Federal Government warning that it is possibly carcinogenic, there are no such concerns with cellulose insulation. Cellulose is also one of the few insulation materials that does not contain fonnaldehyde.
4. CORROSIVENESS The same standard that certifies the safety of cellulose also guarantees its ability to resist corrosiveness. The stringent test which cellulose must pass cannot be passed by rock wool or fiberglass.
5. MOISTURE CONTROL One of the major advantages of natural cellulose fibers over glass or other material fibers is that cellulose breathes. This means that the cellulose absorbs the humidity in the air during periods of high humidity. When humidity drops, the cellulose fibers remit moisture just as readily. In the case of mineral, water condenses on the fibers, displacing the air pockets (which are the insulating medium.) In severe cases, water will run down the inside wall cavity. This can lead to rotting of attic floors and peeling paint on ceilings and walls. Inside walls this moisture can cause structural damage to the bottom plate.
6. DURABILITY An insulation’s durability depends upon how long it will perform the functions of insulation. As the oldest insulation material, cellulose has developed a proven record of performance. Cellulose used in early installations was recently reexamined and found to be functioning just as efficiently as when it was installed.
How Can I Be Sure That the Cellulose I Buy Meets the Federal Standards?
Since October 15, 1979, the Federal Government has required that all new cellulose insulation manufactured carry this label: “This product meets the amended CPSC standard (effective October 16, 1979) for flame resistance and corrosiveness for cellulose insulation.” CPSC is the U.S Consumer Product Safety Commission.
Is Cellulose Insulation Flammable?
Properly treated, cellulose is a flame-resistant material that can be used safely in the home. Since September 7, 1978, cellulose insulation has been manufactured to comply with a new government safety standard. To meet the standard, cellulose must pass two tests that determine its resistance to both flaming and smoldering combustion. A number of experiments conducted under supervision of fire prevention experts have demonstrated that cellulose Insulation, compared to all other types tested is a superior fire barrier and provides substantial additional time for the occupants of a burning dwelling to escape.
I Have Heard That Cellulose Insulation Was the Cause of Several House Fires? Is This True?
According to the U.S Consumer Product Safety Commission (CPSC), improper installation and not the cellulose itself is the cause of insulation fires. CPSC advises against placing any type of insulation over electrical light fixtures, which are recessed in the attic floor. Packing insulation over such surfaces can trap heat inside and raise the temperature of nearby structural members, wiring and electrical fixtures, thus creating a potential hazard. CPSC also advises that all insulation be kept at least three inches away from the sides of recessed lights and away from the exhaust flues of appliances such as furnaces and hot water heaters, in accordance with building codes. All manufacturers of all types of insulation recommend the use of permanent barriers around fixtures and flues to maintain clearance.
Will Cellulose Settle in Walls?
There is a wall cavity density standard established by the Federal Housing Urban Department at 3.54 pounds per cubic foot so as to ensure an optimal wall cavity compaction of cellulose to avoid or minimize insulation settlement in the cavity. Material installed at the proper density will not settle.
What About Corrosiveness?
The same federal standard that requires cellulose to pass flame resistance tests also requires that it pass a very tough corrosion test. This test involves thin samples of steel, copper and aluminum placed in contact with cellulose that has been saturated with distilled water. These materials are kept in a controlled chamber at high humidity and temperature for 14 days. If there is a single pinhole in the metals, the cellulose fails. Cellulose is the only kind of fibrous insulation material that can pass this test.
Does Cellulose Resist Rodents and Insects?
The chemicals used to fire retard cellulose insulation resist rodents and insects.
Does Cellulose Aid Noise Control?
Cellulose is a very effective sound insulator and is often used in condominium developments sandwiched between units for noise control.
How Does Cellulose Insulation Contribute to Energy Conservation?
The Department of Energy has estimated that with adequate insulation, consumers can save up to 30% of the energy used to heart their homes and about 10% of the energy used to cool their homes. Because cellulose is a natural fiber, it has the added advantage of being produced using very little energy. Mineral fiber requires many times the amount of energy to produce as does cellulose.
Does Cellulose Meet the Environmental Protection Agency (Epa) Guidelines on Procurement of Building Insulation?
Yes. Effective February 17, 1989, the EPA designated building insulation products as an item which fails under the Resource Conservation and Recovery Act, 1976. The EPA now requires any procuring agency using Federal funds to revise its insulation specifications and purchase insulation containing the highest percentage of recovered material practicable. The EPA has set a minimum content standard for recovered material in loose fill and spray cellulose of 75% post-consumer recovered paper. Bonded exceeds this standard. Bonded cellulose products are made from approximately 80% recovered newspapers with the remaining portion consisting of chemicals to retard flammability. No other type of insulation exceeds 50% use of recovered material. State and local agencies are required to comply with the EPA procurement guidelines when using federal funds for procuring insulation costing $10,000 or more annually.