On Thu, 09 Feb 2017 16:45:08 -0500, wrote:

Totally different concept than the "core house" and closer to
affordable - and getting into the "highly tornado resistant" home -
effective against most tornados below F5 category with only minor
damage - and still acceptable aesthetics..
We are on the edge of "tornado alley north" up here between the
lakes, with the Fergus, Orangeville, Grand Valley, Durham, Barrie
areas fairly succeptible.
One advantage we have up here is "trailer homes" are virtually
unheard-of except in campgrounds, unlike much of the American
countryside where "redneck bungalows" are very common "permanent
homes" - and they don't stand a chance much above an F1 - and also
much of the American housing stock has no basements. Most homes here
are built on a fully excavated poured concrete foundation, providing a
full basement. We are seeing more and more ICF for that application,
as well as some higher end homes being built completely in ICF - some
with stucco finish, some with concrete or clay brick veneer, and the
occaisional one with vinyl or metal siding. Siding doesn't stand up
well to F2 or above.
Storm shutters are not common here so window and door openings are
still problematic (particularly with siding flying around) - as are
roofs (Flat roofs are not common - not good for snow loads etc)

If you build a tornado proof home, you do not want door and windows.
Eliminate them completely. In order to enter these homes, you want a
tunnel under the home, that exits at least 50 feet from the home, and
runs underground. Six foot diameter concrete sewer pipes can be used as
this tunnel. Where it exits the ground, have a concrete stairway with
concrete walls around it, and a heavy one inch thick steel plate over
the top, that lifts up. and is operated by hydraulic cylinders. This
steel plate should be closed and latched at all times, except when
entering or exiting the home.