From Handbook for Emergencies Office of Civil Defense, Department of Defense 1965
"An protection is better than no protection against fallout. An underground shelter covered with at least 3 feet of earth and properly ventilated is the safest. An ordinary basement, with the windows and entryways sandbagged, will provide some protection. If nothing better is available, a frame house will reduce the danger, especially if you stay on the lowest floor near the center."
The one essential is water; most people can live no more than four days without it. The minimum for a shelter is one quart of fluid per person per day; if space is available near the shelter, a gallon of water a day per person would provide for your comfort, including washing."
The danger in decontamination lies in exposure. Therefore, except for personal decontamination (such as removal of contaminated outer garments), decontamination should be carried out only under official instruction."
In selecting shielding material for any shelter, sand or earth can be substituted for concrete or brick, but for each inch of solid masonry you will need an inch and a half of sand or earth. Adding shielding material to a shelter will improve the protection offered by the shelter, but it also may increase the cost of the shelter."