At the entrance side of the shelter , each roof beam is rested on the inside 4 inches of the block wall .
The outside 4-inch space is filled by mortaring blocks on edge .
The wooden bracing between the roof beams is placed flush with the inside of the wall .
Mortar is poured between this bracing and the 4-inch blocks on edge to complete the wall thickness for radiation shielding .
( For details see inset , fig. 5 .
The first one or two roof boards ( marked `` E '' in fig. 6 ) are slipped into place across the roof beams , from outside the shelter .
These boards are nailed to the roof beams by reaching up through the open space between the beams , from inside the shelter .
Concrete blocks are passed between the beams and put on the boards .
The roof blocks are in two layers and are not mortared together .
Work on the roof continues in this way .
The last roof boards are covered with blocks from outside the shelter .
When the roof blocks are all in place , the final rows of wall blocks are mortared into position .
The structure is complete .
( See fig. 7 .
) Building plans are on page 21 .
Solid concrete blocks , relatively heavy and dense , are used for this shelter .
These blocks are sold in various sizes so it seldom is necessary to cut a block to fit .
Solid blocks are recommended because hollow blocks would have to be filled with concrete to give effective protection .
Bricks are an alternative .
If they are used , the walls and roof should be 10 inches thick to give the same protection as the 8-inch solid concrete blocks .
The illustrations in fig. 8 show how to lay a concrete block wall .
More detailed instructions may be obtained from your local building supply houses and craftsmen .
Other sources of information include the National Concrete Masonry Association , 38 South Dearborn Street , Chicago , Ill. , the Portland Cement Association , 33 West Grand Avenue , Chicago , Ill. , and the Structural Clay Products Association , Washington , D.C. .
Aboveground double-wall shelter
An outdoor , aboveground fallout shelter also may be built with concrete blocks .
( See fig. 9 , double-wall shelter .
) Most people would have to hire a contractor to build this shelter .
Plans are on pages 22 and 23 .
This shelter could be built in regions where water or rock is close to the surface , making it impractical to build an underground shelter .
Two walls of concrete blocks are constructed at least 20 inches apart .
The space between them is filled with pit-run gravel or earth .
The walls are held together with metal ties placed in the wet mortar as the walls are built .
The roof shown here ( fig. 9 ) is a 6-inch slab of reinforced concrete , covered with at least 20 inches of pit-run gravel .
An alternate roof , perhaps more within do-it-yourself reach , could be constructed of heavy wooden roof beams , overlaid with boards and waterproofing .
It would have to be covered with at least 28 inches of pit-run gravel .
The materials for a double-wall shelter would cost about $700 .
Contractors' charges would be additional .
The shelter would provide almost absolute fallout protection .
Pre-shaped metal shelter
Pre-shaped corrugated metal sections or pre-cast concrete can be used for shelters either above or below ground .
These are particularly suitable for regions where water or rock is close to the surface .
They form effective fallout shelters when mounded over with earth , as shown in figure 10 .
Materials for this shelter would cost about $700 .
A contractor probably would be required to help build it .
His charges would be added to the cost of materials .
This shelter , as shown on page 24 , would provide almost absolute protection from fallout radiation .
An alternate hatchway entrance , shown on page 25 , would reduce the cost of materials $50 to $100 .
The National Lumber Manufacturers Association , Washington , D. C. , is developing plans to utilize specially treated lumber for underground shelter construction .
The Structural Clay Products Institute , Washington , D.C. , is working to develop brick and clay products suitable for shelter construction .
Underground concrete shelter
An underground reinforced concrete shelter can be built by a contractor for about $1,000 to $1,500 , depending on the type of entrance .
The shelter shown would provide almost absolute fallout protection .
The illustration ( fig. 11 ) shows this shelter with the roof at ground level and mounded over .
The same shelter could be built into an embankment or below ground level .
Plans for the shelter , with either a stairway or hatchway entrance , are shown on pages 26 and 27 .
Another type of shelter which gives excellent fallout protection can be built as an added room to the basement of a home under construction .
It would add about $500 to the total cost of the home .
The shelter illustrated in figure 12 is based on such a room built in a new home in the Washington , D.C. area in the Spring of 1959 .
Important considerations common to each type of shelter are : 1 .
Arrangement of the entrance .
Radio reception .
The entrance must have at least one right-angle turn .
Radiation scatters somewhat like light .
Some will go around a corner .
The rest continues in a straight line .
Therefore , sharp turns in a shelter entrance will reduce radiation intensity inside the shelter .
Ventilation is provided in a concrete block basement shelter by vents in the wall and by the open entrance .
A blower may be installed to increase comfort .
A blower is essential for the double-wall shelter and for the underground shelters .
It should provide not less than 5 cubic feet per minute of air per person .
Vent pipes also are necessary ( as shown in figs. 9 , 10 , and 11 ) , but filters are not .
Radio reception is cut down by the shielding necessary to keep out radiation .
As soon as the shelter is completed a radio reception check must be made .
It probably will be necessary to install an outside antenna , particularly to receive CONELRAD broadcasts .
Lighting is an important consideration .
Continuous low-level lighting may be provided in the shelter by means of a 4-cell hot-shot battery to which is wired a 150-milliampere flashlight-type bulb .
Tests have shown that such a device , with a fresh battery , will furnish light continuously for at least 10 days .
With a spare battery , a source of light for 2 weeks or more would be assured .
A flashlight or electric lantern also should be available for those periods when a brighter light is needed .
There should be a regular electrical outlet in the shelter as power may continue in many areas .
Other considerations .
-- If there are outside windows in the basement corner where you build a shelter , they should be shielded as shown in the Appendix , page 29 .
Other basement windows should be blocked when an emergency threatens .
Basement walls that project above the ground should be shielded as shown in the Appendix , page 29 .
In these shelters the entrance should be not more than 2 feet wide .
Bunks , or materials to build them , may have to be put inside the enclosure before the shelter walls are completed .
The basement or belowground shelters also will serve for tornado or hurricane protection .
Living in a shelter
The radioactivity of fallout decays rapidly at first .
Forty-nine hours after an atomic burst the radiation intensity is only about 1 percent of what it was an hour after the explosion .
But the radiation may be so intense at the start that one percent may be extremely dangerous .
Therefore , civil defense instructions received over CONELRAD or by other means should be followed .
A battery-powered radio is essential .
Radiation instruments suitable for home use are available , and would be of value in locating that portion of the home which offers the best protection against fallout radiation .
There is a possibility that battery-powered radios with built-in radiation meters may become available .
One instrument thus would serve both purposes .
Your local civil defense will gather its own information and will receive broad information from State and Federal sources .
It will tell you as soon as possible :
How long to stay in your shelter ; ;
How soon you may go outdoors ; ;
How long you may stay outside .
You should be prepared to stay in your shelter full time for at least several days and to make it your home for 14 days or longer .
A checklist in the Appendix ( ( page 30 ) tells what is needed .
Families with children will have particular problems .
They should provide for simple recreation .
There should be a task for everyone and these tasks should be rotated .
Part of the family should be sleeping while the rest is awake .
To break the monotony it may be necessary to invent tasks that will keep the family busy .
Records such as diaries can be kept .
The survival of the family will depend largely on information received by radio .
A record should be kept of the information and instructions , including the time and date of broadcast .
Family rationing probably will be necessary .
Blowers should be operated periodically on a regular schedule .
There will come a time in a basement shelter when the radiation has decayed enough to allow use of the whole basement .
However , as much time as possible should be spent within the shelter to hold radiation exposure to a minimum .
The housekeeping problems of living in a shelter will begin as soon as the shelter is occupied .
Food , medical supplies , utensils , and equipment , if not already stored in the shelter , must be quickly gathered up and carried into it .
After the family has settled in the shelter , the housekeeping rules should be spelled out by the adult in charge .
Sanitation in the confines of the family shelter will require much thought and planning .
Provision for emergency toilet facilities and disposal of human wastes will be an unfamiliar problem .
A covered container such as a kitchen garbage pail might do as a toilet .
A 10-gallon garbage can , with a tightly fitting cover , could be used to keep the wastes until it is safe to leave the shelter .
Water rationing will be difficult and should be planned carefully .
A portable electric heater is advisable for shelters in cold climates .
It would take the chill from the shelter in the beginning .
Even if the electric power fails after an attack , any time that the heater has been used will make the shelter that much more comfortable .
Body heat in the close quarters will help keep up the temperature .
Warm clothing and bedding , of course , are essential .
Open-flame heating or cooking should be avoided .
A flame would use up air .
Some families already have held weekend rehearsals in their home shelters to learn the problems and to determine for themselves what supplies they would need .
If an attack finds you without a prepared shelter
Few areas , if any , are as good as prepared shelters but they are worth knowing about .
A family dwelling without a basement provides some natural shielding from fallout radiation .
On the ground floor the radiation would be about half what it is outside .
The best protection would be on the ground floor in the central part of the house .
A belowground basement can cut the fallout radiation to one-tenth of the outside level .
The safest place is the basement corner least exposed to windows and deepest below ground .
If there is time after the warning , the basement shielding could be improved substantially by blocking windows with bricks , dirt , books , magazines , or other heavy material .
Shelter in apartment buildings
Large apartment buildings of masonry or concrete provide better natural shelter than the usual family dwellings .
In general , such apartments afford more protection than smaller buildings because their walls are thick and there is more space .
The central area of the ground floor of a heavily constructed apartment building , with concrete floors , should provide more fallout protection than the ordinary basement of a family dwelling .
The basement of such an apartment building may provide as much natural protection as the specially constructed concrete block shelter recommended for the basement of a family dwelling .
The Federal Government is aiding local governments in several places to survey residential , commercial and industrial buildings to determine what fallout protection they would provide , and for how many people .
The problem for the city apartment dweller is primarily to plan the use of existing space .
Such planning will require the cooperation of other occupants and of the apartment management .