Fiberglass insulation is made from fiberglass arranged into a texture similar to wool, sometimes called glass wool. Fiberglass insulation is produced in differing thicknesses with different thermal properties. Fiberglass insulation comes in rolls or slabs.

Fiberglass is made by fusing a mixture of sand and recycled glass at a very high temperature. The glass produced is converted into fibers by forcing it through a fine mesh and then cooling it on contact with the air. These fibers are bonded using a binder that cements the fibers together where they intersect.

This fiber mat is heated to polymerize the resin and is calendered for strength and stability. Finally, the glass wool is cut and packaged into rolls or panels under very high pressure. Once that is done, it is palletized and ready for transporting to wherever it will be used.

Fiberglass insulation can be used to insulate flat surfaces such as wall cavities, ceiling tiles, floors and ceilings. It can also be used to insulate around ducting and piping. Fiberglass also is used for soundproofing.

Fiberglass batts or slabs are precut into certain lengths, while blankets are continuous rolls. Gaps between batts can allow heat transfer, so to minimize this, a perpendicular layer of batting or a layer of loose-fill insulation on top can be added. Exposure to fiberglass can cause minor irritation of skin, eyes, nose and throat; so far no significant health concerns have surfaced.