Insulation 101 Today, the two most common, safe and cost-effective options are Cellulose and Fiberglass. Where the confusion begins is that Cellulose is available only in blown material form while Fiberglass can be found in both blown or rolled batting forms.
Fiberglass fill is a loose-fill insulation that is white and fluffy and has a little shine. The insulation may produce a slight shine when exposed to bright light because fiberglass is a glass product. It is very soft, almost like cotton candy, and composed of very fine fibers.
The R-value for cellulose insulation is approximately 3.2 to 3.8 per inch, while fiberglass insulation typically has an R-value of 2.2 to 2.7 per inch. This higher R-value means cellulose insulation can provide the same level of insulation as fiberglass but in a thinner layer.
What Does Cellulose Insulation Look Like? Cellulose insulation is generally grayish or bluish-gray and has a soft, fluffy appearance. It can appear to be similar to loose-filled asbestos but without the shiny fibers. The product's appearance can depend on the materials used to make it.
Other asbestos types have blue, white, brown, or black hues, while cellulose insulation usually looks pastel yellow, gray, or tan with a fibrous or shredded paper texture.
Glass wool insulation has been used in multiple areas of life since the ancient era when Egyptians and Phoenicians used to use it, and Fiberglass came into the equation in 1932. The fiber glass material can differ in colour and can come in pink, white, yellow and green and you can install it anywhere in your home.
Cellulose can be found in modern homes as well as older structures. Dry cellulose insulation is fluffy. It is typically beige, gray, or tan and may resemble papier-mâché, paper pulp, or shredded paper.
What does it look like? Fibreglass insulation is provided in the shape of blankets or sheets. The way in which this type of insulation is created – through the cementing together of the hair-like fibres – results in something that looks and feels like wool.
It is safe to mix cellulose and fiberglass.
When cellulose insulation is blown in on top of another insulation, issues can occur if the existing insulation is wet. If this is the case, it's not a good idea to mix the two. Of all insulations, cellulose is the only insulation in common use that actually manages moisture.
While cellulose insulation itself is treated to be mold-resistant, the surrounding structure may not be. Understanding how and why mold is likely to occur can help you prevent serious structural damage. Given these risks, swift action is imperative if you suspect your cellulose insulation has become wet.
Blanket insulation -- the most common and widely available type of insulation -- comes in the form of batts or rolls. It consists of flexible fibers, most commonly fiberglass. You also can find batts and rolls made from mineral (rock and slag) wool, plastic fibers, and natural fibers, such as cotton and sheep's wool.
It's also fire-resistant. Rodents generally are not drawn to cellulose insulation, either.
Some fiberglass insulation is yellow, while other fiberglass batts are white or pink. What's the difference? Manufacturers use different colors to “brand” their version of fiberglass batt insulation. Owens-Corning has trademarked its pink-tinted fiberglass.
Compared to fiberglass, cellulose is a superb air-blocker. Air moving through a vented attic deposits dirt and dust into fiberglass batts; this is called wind-washing. Dirty fiberglass batts have a significantly reduced R-value. Because it is denser than fiberglass, cellulose is much more resistant to wind-washing.
Certain types of insulation, such as cellulose and mineral wool, can be mistaken for fiberglass due to their similar appearance and use in construction. Asbestos, while less common today, also resembles fiberglass. Each of these materials has its own health implications if inhaled.
While cellulose insulation offers many benefits, its susceptibility to moisture damage is a notable drawback. If exposed to moisture, the paper fibers can absorb water, leading to mold growth, reduced insulation effectiveness, and potential structural damage to the building.
Removing old insulation is generally recommended if it's damaged, contaminated with mold, or infested with pests. However, if the insulation is in decent shape and just needs a boost, adding a new layer on top can be a cost-effective option.
Compressing fiberglass batts enhances the R-value per square inch because the material is packed tightly together. However, compression also reduces the R-value of the batt overall because you lose some inches of insulation when it is packed tightly.
Fiberglass can be tested for in the air and settled dust. The primary air testing method for fiberglass is phase contrast microscopy (PCM), which is also the primary method for testing asbestos in the air.
Insulation That Likely Does Not Contain Asbestos
The following forms of insulation do not contain asbestos but are instead likely comprised of rock wool, fiberglass, or cellulose: Blanket insulation, including batt and roll insulation.
Slowly move the flashlight across the surface of the mattress to inspect it, paying close attention to any areas where you suspect fiberglass particles may have escaped. Fiberglass particles are often small and can reflect light, appearing like tiny sparkling or glimmering specks on the mattress or around the bedroom..
To distinguish between cellulose and asbestos insulation, examine their appearance and texture: cellulose is grayish and fluffy, while asbestos is often found in rigid, white, corrugated panels. Use caution asbestos requires professional testing and handling due to health risks.
Upon close inspection, fiberglass fibers may look like translucent, plastic threads. They typically have a shiny surface with a white or off-white color. If you think you see fiberglass on the outer surface of your mattress, do not touch it to avoid skin irritation and other harmful physical effects.
Modern cellulose insulation, made with recycled newspaper using grinding and dust removing machines and adding a fire retardant, began in the 1950s and came into general use in the US during the 1970s. The market for insulation increased following the oil embargo of 1973-74.