Fiberglass is available in two forms: as batting (rolled) or as a loose-fill (blown) material. Many homeowners typically feel they want rolled insulation, but once they do the research they find otherwise. Fiberglass insulation, whether rolled or blown, has several negative characteristics of significant concern. Please do your research before using fiberglass!
Fiberglass is glass fibers; the fibers are very small, rigid and sharp. On account of this, all fiberglass products have a hazard/warning label on them clearly relating to the danger of cancer, upper respiratory irritation and other related illness. Anyone who has ever worked with fiberglass can attest to the terrible “itch”. Contractors or workman are often hesitant or charge more to work in an attic that has fiberglass.
Homeowners often feel that the attic area is separate from their homes living quarters, but the increased use of recessed lighting, HVAC units and other devices located in the attic has lead to a surprising amount of air interaction between attic area and living quarters below. When a home develops health issues for the occupants, environmental companies are quick to remove fiberglass insulation from the attic or at least blow Cellulose insulation over the Fiberglass to seal and encapsulate it.
Fiberglass does not carry a lifetime warranty. Blown fiberglass is known for settling and packing after it’s installed. Much like the cotton-candy that it resembles, the very nature of blowing Fiberglass tends to fluff the material up, the product then settles over time. The rolled fiberglass minimizes the fluffing-effect, but the rolled-in application by its nature is several strips that run between the ceiling joist. It doesn’t seal over the top of the framing and has a compromised fit around the plumbing, piping and conduit that runs throughout the attic, so while the rolled Fiberglass won’t settle and pack as much, it’s a compromised fit to begin with.
Also, Fiberglass is less efficient as compared to cellulose; fiberglass must be over 15 plus inches thick to produce an R-38 rating, while cellulose only needs to be 10.4″ in order to attain the same R-38 performance. Anyone who has been in an attic can tell you it’s more difficult to work in over a foot-thick of itchy Fiberglass then 10″ of soft Cellulose!
Fiberglass does not have any insect or termite resistant qualities, in fact, fiberglass makes a splendid home for rodents and vermin. Quite often we find evidence of rats and mice living in the fiberglass. Given some moisture, fiberglass also provides an excellent media for mold & mildew to grow and foster. By comparison, Cellulose is mold, mildew and fungal resistant, as well as rodent and insect resistant.