Typically made with 20-30% recycled industrial waste and similar post consumer content. Fiberglass blankets are provided in continuous rolls however batts are precut.
THE UPSIDE: This material is not flammable, with the possible exception of its facing. Blankets can cover joists and studs, as well as the space between them.
THE DOWNSIDE: Blankets can be difficult to hang under floors between joists. Gaps between batts can defeat the purpose of the insulation because they invite air infiltration or condensation. If you live in areas of high moisture such as the shoreline the fiberglass can get moist and lead to mold. Also, fiberglass insulation diminishes overtime and loses its effectiveness. If someone in your home is allergic to dust and other allergens this insulation will not help their situation.