Shielding material is any substance that would absorb and deflect the invisible rays given off by fallout particles outside the house, and thus reduce the amount of radiation reaching the occupants of the shelter. The thicker or denser the shielding material is, the more it would protect the shelter occupants. Some radiation protection is provided by the existing, standard walls and ceiling of a basement. But if they are not thick or dense enough, other shielding material will have to be added. Concrete, bricks, earth and sand are some of the materials that are dense or heavy enough to provide fallout protection. For comparative purposes, 4 inches of concrete would provide the same shielding density as: --5 to 6 inches of bricks. --6 inches of sand or gravel . .\ May be packed into bags, cartons, boxes, --7 inches or earth. . . . . . ./ or other containers for easier handling. --8 inches of hollow concrete blocks (6 inches if filled with sand). --10 inches of water. --14 inches of books or magazines. --18 inches of wood. HOW TO PREPARE A HOME SHELTER If there is no public fallout shelter near your home, or if you would prefer to use a family-type shelter in a time of attack, you should prepare a home fallout shelter. Here is how to do it: * A PERMANENT BASEMENT SHELTER. If your home basement--or one corner of it--is below ground level, your best and easiest action would be to prepare a permanent-type family shelter there. The required shielding material would cost perhaps $100-$200, and if you have basic carpentry or masonry skills you probably could do the work yourself in a short time. Here are three methods of providing a permanent family shelter in the "best" corner of your home basement--that is, the corner which is most below ground level. If you decide to set up one of these shelters, _first get the free plan for it_ by writing to Civil Defense, Army Publications Center, 2800 Eastern Blvd. (Middle River), Baltimore, Md. 21220. In ordering a plan, use the full name shown for it. CEILING MODIFICATION PLAN A If nearly all your basement is below ground level, you can use this plan to build a fallout shelter area in one corner of it, without changing the appearance of it or interfering with its normal peacetime use. However, if 12 inches or more of the basement wall is above ground level, this plan should _not_ be used unless you add the "optional walls" shown in the sketch. Overhead protection is obtained by screwing plywood sheets securely to the joists, and then filling the spaces between the joists with bricks or concrete blocks. An extra beam and a screwjack column may be needed to support the extra weight. Building this shelter requires some basic woodworking skills and about $150-$200 for materials. It can be set up while the house is being built, or afterward. ALTERNATE CEILING MODIFICATION PLAN B