The subfloor of the house should be insulated with a vapor barrier to prevent moisture build up and mold. If your crawl space isn’t ventilated, the walls should be insulated instead. Prodex is a 5mm reflective, reinforced foil which is perfect for this application.
Garage ceiling insulation is installed from the garage area through 2″ holes. It’s blown in through a tube inserted into the cavity, filling the bays to capacity. Yesterday’s building codes require minimal garage ceiling insulation and no wall insulation in garage walls.
Many homes have no insulation in the walls if constructed before 1950 and have minimal insulation if built between the 50’s and 70’s. The procedure to re-insulate the walls can be done from the interior or exterior of the house with little or no damage to the wall.
Attic insulation is the most important area to upgrade in existing homes. The building code in the early seventies required only 4″ in the attic (R-11). Today’s requirement is up to 15″ of fiberglass or 14″ of cellulose. Yes, cellulose has more R-value per inch and cellulose provides 100% coverage vs. 80% coverage with fiberglass.
