On Sun, 17 Jul 2005 16:00:55 -0500, Vic Dura
wrote:

Here is an article claiming that a 2400 sqft "round" house (approx 28'
dia.) is more resistant to wind than a rectilinear (square or
rectangle) house.

Um, your math is a bit off.


http://home.hiwaay.net/~vdura/Images/scan2.jpg

Any comments/opinions on the veracity of the claims?

Plenty.

First, the house isn't "circular" but from inspection appears to be a
regular polygon with twelve sides (dodecagon).

Second, the article claims that there are no flat sections wider than
4' on the house.

The enclosed area (A) of a polygon can be found from:

A = (n * S^2 * cot (180 / n)) / 4

whe

n = the number of sides = 12

S = length of one side = 4

From "Reference Data for Radio Engineers", 5th Edition, pg 44-1.

Solving: A ~ 179 sq. ft. For a two story house then the area is ~
360 sq. ft. or a long way from 2400 sq. ft.

A sanity test: Let the twelve sides approximate a circle. The
circumference is then 12 * 4 = 48'. The diameter is then 48 / pi ~
15.28. The radius ~ 7.64 and the area is pi * radius ^2 ~ 183. Close
to more exact 179.

So bogus claim no. 1 is that the house has no flat surfaces greater
than 4' or conversely, it isn't 2400 sq. ft.

It's more likely and sensible that the sections are 8' wide, in which
case the area (per floor) is more like 720 sq. ft. (Enough snooping
on Deltec's web site confirms my suspicion)

So unless there is a "poop deck" (pun intended) on the back side of
this thing it still isn't 2400 sq. ft. If there is some poop on the
back then it's not "circular" and the professed wind loading advantage
is bogus claim no. 2.

I'm not fluent with the IBC or UPC wind loading stuff, but do have
some insight into wind loading on radio towers and antennas. So I
know that a smooth cylinder of given projected area has lower wind
pressure per unit area (drag) than a flat surface. So the "circular"
house probably has some advantage. That said, a 720 sq. ft. dodecagon
has a projected width (short aspect) of 30 ft. A square house of the
same area has a projected width of ~27 ft.

There are no doubt some advantages to the roof construction as well,
but I'm not going to try to mess with that.

Not living in hurricane country (please please please -don't- move
here), I have no first hand knowledge but from my reading it appears
that an awful lot of damage is done, not by the effects of wind on
your house but on the damage done by the flying debris from the houses
that weren't so well constructed.

I'm reminded of a Fine Homebuilding Magazine article about a
"hurricane proof" house built on some offshore island. It was no
sooner done than a light plane crashed into it and the resulting fire
completely destroyed it (and the unlucky pilot).