thickness of other shielding material (see page 25) for overhead
shielding from fallout. More posts or braces may be needed to support
the extra weight.

After the roof has been shielded, better protection can be provided by
blocking the entrance way with 8-inch concrete blocks or an equivalent
thickness of sandbags, bricks, earth or other shielding material, after
all occupants are inside the shelter. A few inches should be left open
at the top for air. After particles have stopped falling, the outside
door may be left open to provide better ventilation.

If shielding material is not available for the entrance way, shelter
occupants should stay as far away from it as possible. They also should
raise the outside door of the storm cellar now and then to knock off any
fallout particles that may have collected on it.


USING THE CRAWL SPACE UNDER YOUR HOUSE

Some homes without basements have "crawl space" between the first floor
and the ground underneath the house. If you have this space under your
house--and if the house is set on foundation walls, rather than on
pillars--you can improvise fallout protection for your family there.

First, get access to the crawl space through the floor or through the
outside foundation wall. (A trapdoor or other entry could be made now,
before an emergency occurs.)

As the location for your shelter, select a crawl-space area that is
under the center of the house, as far away from the outside foundation