Table 1. Types of Insulation--Basic Forms

Form Method of Installation Where Applicable Advantages
Blankets: Batts or Rolls
  • Fiber glass
  • Rock wool
Fitted between studs, joists and beams All unfinished walls, floors and ceilings Do-it-yourself

Suited for standard stud and joist spacing, which is relatively free from obstructions

Loose-Fill (blown-in) or Spray-applied
  • Rock wool
  • Fiber glass
  • Cellulose
  • Polyurethane foam
Blown into place or spray applied by special equipment Enclosed existing wall cavities or open new wall cavities

Unfinished attic floors and hard to reach places

Commonly used insulation for retrofits (adding insulation to existing finished areas)

Good for irregularly shaped areas and around obstructions

Rigid Insulation
  • Extruded polystyrene foam (XPS)
  • Expanded polystyrene foam (EPS or beadboard)
  • Polyurethane foam
  • Polyisocyanurate foam
Interior applications: Must be covered with 1/2-inch gypsum board or other building-code approved material for fire safety

Exterior applications: Must be covered with weather-proof facing

Basement walls

Exterior walls under finishing (Some foam boards include a foil facing which will act as a vapor retarder. Please read the discussion about where to place, or not to place, a vapor retarder)

Unvented low slope roofs

High insulating value for relatively little thickness

Can block thermal short circuits when installed continuously over frames or joists.

Reflective Systems
  • Foil-faced paper
  • Foil-faced polyethylene bubbles
  • Foil-faced plastic film
  • Foil-faced cardboard
Foils, films, or papers: Fitted between wood-frame studs joists, and beams Unfinished ceilings, walls, and floors Do-it-yourself

All suitable for framing at standard spacing. Bubble-form suitable if framing is irregular or if obstructions are present

Effectiveness depends on spacing and heat flow direction

Loose-Fill (poured in)
Vermiculite or Perlite
not currently used for home insulation, but may be found in older homes