Cellulose — A Good Insulation Choice

For many years, fiberglass has been the standard against which all other insulation materials were judged. But traditional fiberglass insulation has some down sides. One is its inability when used in batt form to fill in tiny spaces in walls and other places. Another is its tendency to let air pass through it. When you think about the fact that 20% or more of your heat and air conditioning can go through fiberglass, it becomes a significant drawback.

Now there is another option. Cellulose is a good insulation choice. Cellulose is made up of about 80% recycled newspaper and other plant-based material. This makes it an excellent “green” choice for insulation.

You might wonder about it being an insulation that would burn easily since it’s largely paper. Not so. Cellulose is treated with non-toxic borate compounds to make it resistant to fire, insects, and mold.

When cellulose is densely packed in walls and other spaces, it limits air movement and drafts better than fiberglass. Cellulose can lead to a 26% cost savings in heating and cooling your home.

Types of Cellulose Insulation

Four types of loose-fill cellulose insulation each have optimum uses. Dry cellulose is often used in older homes by blowing it into the walls through holes drilled at the top of the walls. It can be used in newer construction also with the use of netting to hold it in place temporarily. There can be as much as 20% settling with this type of cellulose, but using a dense-pack application can reduce this settling.

Spray applying cellulose is another way to use this insulation in new construction. Water is added to the product along with a moisture retarding chemical like chlorine to keep mold from growing. Applying cellulose insulation this way requires a wait time of at least 24 hours before covering the walls.

Stabilized cellulose is used mainly in sloping roofs in attic spaces. Water is added to provide adhesion. This leads to less settling and uses less cellulose.

Low-dust cellulose is the fourth type commonly used. Every kind of insulation produces some amount of dust when applied, making dust masks at the least necessary for those doing the applying. This type of cellulose insulation has a small amount of oil or other dust-dampener added to reduce dust.

Advantages of Cellulose Insulation

Advantages of cellulose insulation include:

Thermal performance. Cellulose insulation in its loose form compares well with other types of insulation with lower cost. However, it is lower than polyurethane foam insulation.

Overall efficiency of insulation. Cellulose is excellent at fitting around pipes and electrical outlets, filling in small spaces that could lead to air pockets in other types of insulation. The dense pack type of cellulose is especially good at forming highly-efficient insulation. It typically works 20-30% better than fiberglass at lowering heating energy. Cellulose has a lower R-value per inch installed than foam, but costs less as well.

Sound reduction. Compared to fiberglass, cellulose reduces sound slightly better.

Protection against mold. The borates added to cellulose prevent mold growth very well. Some customer reports show mold doesn’t grow in cellulose even after several months of being saturated, as long as the installation is appropriate. The borates also give cellulose highest fire safety rating.

Vapor barrier. Since cellulose completely fills the spaces where it’s applied, it helps prevent moisture issues. Most manufacturers don’t recommend using a vapor barrier with cellulose.

How Is Cellulose Applied?

A specialized insulation blower is used to apply cellulose insulation. A long hose is used by the contractor to guide the flow of cellulose into place. Controls allow the contractor to decide on the density of the insulation. There is a more even, consistent application of cellulose when applied by a professional.

For the best installation of any insulation you choose, Weathertight professionals do their best to assure you of the best installation. Brad Preston and his brother Brian, are ready and willing to talk with you about the best insulation for your home.