I can't imagine what kind of ceiling is going to stick
around after the floor joists have blown off, except
maybe a concrete slab.
Can anything wood resist the forces of a tornado?
I don't know. I'd expect you'd need a lot of bracing if
you wanted to try.
You could do something like anchor the joists to
the sill plate bolts with steel brackets. gfretwell
mentioned Simpson ties. They do have hurricane
ties for decks, but with those any pull is against
the tie itself, so they're very strong even though
they're not so thick. If you use ties to the sill plate then
the resistance to pull will be weaker because it will
be pulling the nail out. So I guess if it were me I'd
want the joists anchored to the actual bolts coming
out of the foundation wall, and then put 3/4" plywood
on the bottom of the joists. The idea that comes to
mind would be a thick angle iron, possibly even folding
over the top of the joist. Custom made, probably.
But if you're building a new house then why not
build the whole thing with extensive bracing and
interconnections? I would think there must be officially
tested methods for that, just as there are for
| The cellar floor slab is formed and ready to pour ... coming next will
| the (heavy) block walls . Got the rebar and filled columns figured out ,
| next up is the attachment of the floor joists to the top of said wall .
| plan is to set some carriage bolts into the top run of block at suitable
| intervals and use those to secure a 2X plate - width TBD . I'll want to be
| able to secure a ceiling of some type to an overhanging top plate ,
| independent of the structure above - this will also serve as a storm
| The question is , how best to secure the floor joists to that same top
| plate , so that they are both stable and secure and yet if a storm strong
| enough comes thru to part without taking my ceiling with it . Or , should
| use the floor structure as the top/ceiling , and let the wall/floor
| interface part if it comes to a tornado etc ? We're actually pretty
| sheltered , down in a pretty deep bowl - when the tornado took out half of
| the nearest town (and many others on it's way to here) it skipped over The
| Holler , all we got was some torn up trees .
| Possibly pertinent detail - the bottom part of the structure - probably
| to window sill height- will be clad with native stone . Probably 5-6"
| , depending on what I collect and bedded on a footing 16" below grade -
| frost line is at around 12" .