Walter Avery, age 12, of Lake Charles, La., for his question:
HOW DO YOU INSULATE A HOUSE?
Insulation is a material that protects against heat, cold, soundor electricity. The insulation of a house is important to comfortable, economical living. Generally speaking, a house is insulated by filling the hollow spaces between the studs in the walls and the spaces between the ceiling joists with insulation material.
Several types of insulation material are used for homes: batt, blanket, loose fill, rigid and reflective insulation. Batt insulation is made in soft, flexible units that fit between rafters and joists. Batts can be made of fireproof fibrous materials such as treated wood fiber, hair felt, flax fiber, eel grass or even shredded paper.
The material in a batt is stitched between two sheets of waterproof paper. Batts are available in thicknesses of up to one inch.
Blanket insulation is made in the same way and of the same materials as batt insulation. However, insulation comes in long rolls rather than pieces: The roll usually contains about 100 square feet.
Loose fill insulation comes in bulk form in bags or bales. The material may be made of granulated cork, expanded mica, mineral wool in the form of pellets or other matter. Loose fill insulation is poured or blown into place.
Rigid insulation is made of thick sheets of fiberboard nailed to outside walls in place of wood sheathing. The sheathing is then or covered with wood siding or brick or stone veneers. Reflective insulation is made up of thin copper or aluminum sheets, or of aluminum or copper foil. It also includes coatings applied to the surfaces of rigid insulation, plasterboard or even heavy paper. The bright metallic surfaces of these reflective materials actually help to reflect heat waves.
Building experts tell us that the heat loss from uninsulated houses is so high that insulation in the outside walls and in the ceiling of the top story will pay for itself in just a few years in lower fuel bills.
Soundproofing is a type of insulation. There are two types of soundproofing: the kind that consists of sound absorbing or sound deadening materials placed on walls and ceilings to reduce echoes and the type of soundproofing that reduces the sound transmitted from room to room by vibration of the walls and floors.
Materials used for sound absorbing or sound deadening include hair felt covered with burlap, perforated fiberboard, corkboard and special types of acoustical plaster and tiles. Many cloth curtains and upholstered furniture are also effective as sound waves penetrate these items, a part of their energy is converted by friction into heat energy.
To reduce sound transmitted from room to room by vibration of the walls and floors, heavier building materials such as brick, stone or concrete can be used. Floor coverings such as carpets, heavy linoleum, rubber tile and cork tile can also help insulate against sound producing vibrations.