A number of materials have been used to insulate homes. Many of these materials are still effective and in use and are briefly described below.

FIBERGLASS: Fiberglass is probably the most common and versatile insulation on the market today. It is low cost and has good insulating values. It is available in batts, blankets and loose.

MINERAL WOOL: Most often called rock wool. It looks like dirty wool and is dusty when handled. It was very popular in the 50’s and early 60’s. The insulating qualities are quite good, however the quantity is often inadequate by today’s standards and additional insulation should be installed.

CELLULOSE: This is an inexpensive insulation made of recycled materials most notably newspapers. The process consists of grinding up old newspapers mixed with borax or aluminum sulfide to add fire proofing. It has insulating qualities a little better than fiberglass when first installed. As it settles over time, the insulating qualities diminish to slightly less than fiberglass. A major advantage is that it does not have the irritating features that fiberglass and rock wool have.

MICA: This product is made from the mineral mica and is often called vermiculite or perlite. It is an attractive material when filling voids, however, its insulating qualities are substantially less that other types of insulation. The insulating qualities are only fair and the quantity is often inadequate by today’s standards. The addition of more insulation is often advised.

SILVA WOOL: This is a product manufactured by the lumber industry. It consists of wood slivers treated with a fire retardant. The most common wood appears to be cedar that is resistant to rot and pests. The insulating qualities are quite good, however the quantity is often inadequate by today’s standards and additional insulation should be installed.

Increasing the levels of insulation in your home is often a wise energy investment. If there is room in the attic, insulation should be upgraded at least to the current code level. In Washington State, this code is R 30 or R 38, depending on where one lives.

One of the most difficult problems with adding insulation is providing a vapor barrier. Most vapor that migrates to the cavity probably does so because of the passage of warm house air through holes, cracks, switch plates, sockets and the like. If the air is cooled to the point at which the moisture can no longer exist as a vapor, condensation occurs. At certain outside temperature levels and indoor humidity levels, that point might be in the layer of insulation. This is more of a problem for the porous or fibrous insulation. This problem can be avoided by adding vapor barriers, providing proper ventilation, caulking cracks and holes in the interior surface of the wall, and using gaskets on switch plates and sockets.

Some materials that qualify as vapor barriers are polyethylene and aluminum foil. It is placed on the warm side of the insulation.

Moisture problems will be greatly reduced if the generation of moisture vapor is dealt with at the source. Vent bathrooms, kitchens, and laundry rooms to the outside. Make sure the attic and crawl space are properly vented to rid them of any moisture that might accumulate.