What is Fiberglass?

Michael Pollick
Michael Pollick

In the strictest sense, fiberglass is a trademarked product of the Owens Corning company, invented in 1938 and marketed as a home insulation product (Fiberglas). While home insulation remains one of its most common applications, the name itself has become a generic term for any material containing thin fibers of glass formed into a woven layer or used as reinforcement.

The hulls of small to medium sized boats are routinely made of fiberglass.
The hulls of small to medium sized boats are routinely made of fiberglass.

The "glass" in fiberglass is the same basic substance used in windows and glassware. Molten glass is extruded through ultra fine openings measured in microns, resulting in thread-like formations which can be woven together to form a rough cloth or patch. Different resins can then be added to this material, allowing it to be formed and pressed into molds. The result is a heat-resistant, lightweight panel ideal for electronic circuit boards or support structures for complex machinery.

Inhaling fiberglass particles can result in health issues.
Inhaling fiberglass particles can result in health issues.

Fiberglass mixed with resins can also be used to form the shell of racing cars or other custom designs. Repairs can be made with a commercial product called Bondo, which is essentially a fiberglass tape mixed with a quick-curing resin. When this material is used for car body work, it can be sanded smooth and painted to match the rest of the vehicle. It may not have the inherent tensile strength of steel, but a skilled auto body repairman can often match the section repaired with fiberglass and resin seamlessly with the rest of the car.

On a larger scale, fiberglass can be mixed with other materials to form a thick insulating pad. The pad containing fiberglass is attached with adhesive to an aluminized backing paper. The material is then divided into standard widths which will fit squarely between the vertical studs (exposed support boards)of an unfinished wall. Copious amounts of fiberglass are packed into the space between the exterior wall and the interior wallboard. Once all of the insulating material has been placed, panels of drywall can be put up to finish off the room.

Fiberglass as a building and insulating material is very versatile, but it is not always easy or safe to use. Because the main ingredient is real glass, microscopic bits of glass powder or shards are often formed. Those installing it insulation should always wear gloves, safety glasses and masks. The glass shards and powder can remain on the skin even after several washings. These particles can be very irritating to the lungs and hands and extremely damaging to the eyes. A protective hand cream barrier may help prevent some fiberglass powder buildup.

If you work around the compressed form of fiberglass (i.e. electronic boards), compressed air may be the best way to remove tenacious residue. Avoid touching eyes or other sensitive areas while working with this material in any form. If the powder does enter the eyes, use plenty of clean water or approved eye wash and visit an eye doctor for emergency examination.

Skilled auto body repair workers can fix damage to fiberglass bodies of cars.
Skilled auto body repair workers can fix damage to fiberglass bodies of cars.
Michael Pollick
Michael Pollick

A regular wiseGEEK contributor, Michael enjoys doing research in order to satisfy his wide-ranging curiosity about a variety of arcane topics. Before becoming a professional writer, Michael worked as an English tutor, poet, voice-over artist, and DJ.

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Discussion Comments


can you fiberglass over thin carpet?


My daughter works at a beach as a lifeguard. She recently got fiberglass in the bottom of her feet. How do we get the fiberglass out? Will it eventually get into her skin? What can we do to help her walk without pain?


I would like to set up a fiberglass helmet manufacturing unit. Can i know the process of helmet manufacturing and other details? -- gaurish


Does anyone know what material would be suitable to insulate the exterior of a BBQ smoker? Mine is made of rather thin sheet metal and does not maintain a consistent temperature.

I'm thinking I could somehow wrap the unit with common household fiberglass batts, covered by plywood, maybe. Obviously high temperatures aren't typically what smokers do, so I am figuring no higher than 250-300 degrees.

I appreciate any advice! Ches, Columbia, SC


My child at the age of five, has been in contact with fiberglass insulation. I do believe that he has some in his little hands. I would like to know how long it takes for this stuff to work out..if it works itself out at all, and in the meantime *what* can I do to help him with the itching and the redness?? It's been 4 days now, how much longer??


I have fiberglass insulation in the house inside the walls can this be toxic to anyone with MCS multiple chemical sensitivity?


I have a Fiberglass storage tank and need to estimate the weight. The tank is made of resin and chop and is approximately 3/8" thick The tank has about 880 square foot of surface area What I need to know is the approximate weight of 1 Square foot of Fiberglass 3/8" thick.


I have been researching insulation and have an extremely reliable (as in my science teacher approves) source that shows that fiberglass is listed by the FDA as a possible carcinogen. If there's fiberglass exposed, that's not good. Of course, if it's in the wall, unexposed, and has been there for years, it's safer to leave it there.

Why did they put up insulation after the room was almost finished?


The carpet should never have been installed before the insulation was done. And no, you will never be able to get all of the fiberglass particles out of the carpet. For the health of the whole family I would demand (with a lawyer, if necessary) that the contractor replace the carpet.



I had fiberglass insulation thrown all over my sons apartment carpet at his college apartment. We would like to know if it is possible to clean it up?


Does anyone know if fiberglass insulation that goes in the attic comes out of carpet easily? My daughter is having a new house built and the workers got piles of the insulation all over the brand new carpet in the main living room. She is concerned that those small particles of glass will not come up with just vaccuming and she is going to have a baby soon. Could anyone advise?

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