Glass fiber, best known by its trade name "fiberglass", is one of the most common insulation materials and is standard in newly constructed wood-frame homes. It is made of long, spun glass fibers coated with resins to create bonding between the fibers.
Fiberglass has the advantages of being relatively inexpensive, easy to install, resistant to moisture damage while being relatively nonflammable. In batt or blanket form, it has the advantage of not settling and creating gaps after installation. In its rigid board form, it offers the advantages of high R per inch and some structural stability.
Glass fibers can be irritating to the skin and lungs, so the insulation requires some special handling. Masks, gloves, long sleeves and other protective apparel should be worn when handling this type of insulation.