Cover the entire trench with lumber (or with house doors that have been taken off their hinges), except for about 2 feet on the short side of the L, to provide access and ventilation.
On top of the lumber or doors, pile earth 1 to 2 feet high, or cover them with other shielding material.
If necessary, support or "shore up" the walls of the trench, as well as the lumber or doors, so they will not collapse.
Dig a shallow ditch, 6 inches deep and 6 inches wide, parallel to and 4 feet from the outside wall of your house.
Remove the heaviest doors from the house. Place the bottoms of the doors in the ditch (so they won't slip), and lean the doors against the wall of the house.
On the doors, pile 12 to 18 inches of earth or sand. Stack or pile other shielding material at the sides of the doors, and also on the other side of the house wall (to protect you against radiation coming from that direction).
If possible, make the shelter area deeper by digging out more earth inside it. Also dig some other shallow ditches, to allow rain water to drain away.
An Improvised Shelter on the Ground Floor
If your home has no basement or storm cellar (and no crawl space that is surrounded by foundation walls up to the first floor), you can get some limited fallout protection by improvising a fallout shelter on the first or ground floor of your house. However, this type of shelter probably would not give you nearly as much protection as the other types of improvised shelters described in this chapter.