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.

An underground reinforced concrete shelter can be built by a contractor for about $1000 to $1500, 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.