In both his book Rawles on Retreats and Relocation and in his survivalist novel, Patriots: A Novel of Survival in the Coming Collapse, Rawles describes in great detail retreat groups "upgrading" brick or other masonry houses with steel reinforced window shutters and doors, excavating anti-vehicular ditches, installing warded gate locks, constructing concertina wire obstacles and fougasses, and setting up listening post/observation posts (LP/OPs.) Rawles is a proponent of including a mantrap foyer at survival retreats, an architectural element that he calls a "crushroom".
We had been friends for at least 12 years and knew that the one was Bi Polar, she seemed to have her act together over all, but when we allowed them to live with us, within just a couple of months, problems started that would potentially cause any type of cooperative survival situation to go right down the toilet. We still feel sad about losing the friendship we had shared, but have to admit that God blessed us with knowing what sort of crap COULD have happened very easily in a SHTF situation.
Earthquakes, tornadoes, and hurricanes can cause you to leave your home or even be trapped there. Roads could be blocked due to fallen trees, power lines, or even damaged earth from the natural disaster. Rescue crews can not be in all places at once. You may have to wait it out for quite a while before its over. You won't be able to go to the store or to the corner market.