When I was designing our house, we wrestled with the idea of a storm shelter, which got down to in ground near the house/under the house or built INTO the house as the house structure.
As mentioned, FEMA has all sorts of good information on building storm shelters.
I had pretty much decided to build an in house shelter but then we had to decide which room(s) would be the shelter. The problem we had was that there was no good room that we could duel use as a storm shelter. Our master bathroom or closet was the best we could do but it would have some design hits that we did not like. The extra wall thickness of the storm room would also force us to expand the size of the house a bit but that little expansion was going to cost quite a bit of money. Just a simple estimate put the initial extra cost at around $10,000. Then there was the expense of the materials to build the room and how would the shelter door match the rest of the house?
So I had a cost but then what was the risk? I did some digging and found out that my county does not have many tornadoes, and the ones we do get, are small ones with a very strong one being an F2 every once in awhile. We would survive a hit by an F2 just sitting in the house. Our county is odd in that tornadoes and strong weather seems to by pass us for some reason. I have watch fronts moving our way and man times they split apart or disappear as they get to us. It is very odd but I am thankful. :thumbsup: We had a very bad set of storms that came through back in the fall with multiple tornado warnings and watches. Very bad stuff with schools having to actually perform their tornado procedures. Knock on wood, but the mess did not do anything in our county. As granny would say, count your lucky stars.
We did not build a strong room. BUT, if we were in a different part of the state that receives stronger tornadoes, the decision would have been different. Either a strong room in the house or a concrete below grade shelter outside. Any shelter needs at least two ways out AND doors/hatches that open IN along with supplies for a long stay and tools to cut your way out.
Later,
Dan