One of my buildings is block on slab...
I have collected salvaged concrete and brick from city sidewalk work and construction sites that I have worked on.
I stacked the 40-100 lb pieces of rubble, not mortared, 3 feet tall and 3 feet wide around the base of my building. It helps with drainage... (the
slab doesn't stay wet anymore) which was one of the main reasons this particular building was abandoned... and it heavily fortifies the structure
from, say, a car coming off the main road or bullets from urban combat. Flowering vines over the rubble keep code enforcement officials at bay.
Personally... I'm headed out of downtown very shorty...
Off to build log cabins in the hinterlands.
I am,
Sri Oracle


And to cover your whole house
in sheet metal isn't going to work... If a tornado hits your house same thing... Earthquake, same thing.. Not much you can do when that happens...
Instead use a bunker setup, dig a hole fairly deep, already in a dip on the landscape so it's under the plain... This will hide you really well and
would take less steel to protect yourself... Protects you from wind and would also protect you from a blast because the blast would travel over the
top of you... Shield the inside with copper screen to prevent any signals leaving or entering your location, run a few hard lines in, store enough
food for 2-3 months, have a bed, small toilet and shower, kitchen like a regular house but mostly under ground.. 