Can Fiberglass Insulation Be Installed Over Cellulose Insulation?
- When the cost of heating a home increases, more people take a second look at their insulation to find out if they can improve it and save money. Cellulose insulation can be augmented by spraying more cellulose on top of it, but there are other ways to accomplish the same end. If you pile too much cellulose insulation in one place, you run the risk of increasing its weight to the point where it compacts, thus reducing its insulating effectiveness.
- Fiberglass insulation is manufactured in large rolls that are usually installed between the studs in a house wall. Fiberglass can also be rolled out on top of the joists in an attic, covering the cellulose insulation and adding the insulative value of the fiberglass to the cellulose. Install the fiberglass perpendicular to the joists; this decreases the likelihood of a roll of fiberglass sinking down into the cellulose and compacting it. Arrange the fiberglass batts so you won't have to walk on them once they're installed; you won't know where the joists are, and if you step between the joists, you could put your foot through the ceiling below.
- Because heat rises, the attic is an important part of the house to insulate properly. Poorly insulated attics not only lose heat in the winter, they also contribute to an excessively hot house during the summer, because they can get hot under direct summer sun. Covering the entire attic area with fiberglass insulation in addition to cellulose can keep your home significantly warmer in the winter and refreshingly cooler in the summer.
- Roofs are designed so that air can enter at the eaves, rise up underneath the roofing as it warms and exit at the ridge through either a vent or a cupola. When you install fiberglass insulation directly under the eaves of a roof, be sure that you don't press it against the rafters. This will interfere with the ventilation of the attic and could lead to problems with moisture and overheating. Properly installed fiberglass insulation will isolate the living area below from the attic area above, while allowing the attic to be properly ventilated.
