Round House more wind resistant?

[G Henslee]

I read the article. Makes sense. Now you know why a baseball is round and not square.

Anything else?

[Vic Dura]

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.

Any comments/opinions on the veracity of the claims?

[Wes Stewart]

Um, your math is a bit off.

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

where:

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).

[Vic Dura]

Yeah, thanks for catching that.

I agree. Looking at the flat surfaces with the windows & doors relative to the size of the sat. dish and the man, it didn't look right. The panels with the two windows certainly did not look like 4' panels.

That size is more consistent with the size of the other known objects in the image and as you say seems like a more reasonable size for prefab panels.

[Andy Sullivan]

Veracity? The question is, why *wouldn't* it be true? Geodesic dome homes even moreso.

[Edwin Pawlowski]

Ever see a rectilinear airplane, boat, rocketship?

[~^Johnny^~]

[HeyBub]

A "round" house underground is even more wind resistant.

[Goedjn]

1: The house in the picture isn't round, it's an octagon, but mostly, the same principles apply. 2: Yes, given similar construction, the round house should be more wind-resistant. 3: But not enough to matter. A box-shaped house is more space efficient, and cheaper to build. So if you're comparing PRICE instead of construction technique, you're probably better off with the box.

--goedjn

[Gort]

And, in a roundhouse those damned locomotives take up so much space! ;-)

[Michael Daly]

Ballast - that's why they're wind resistant.

Mike

[CL (dnoyeB) Gilbert]

The force due to wind will be proportional to the surface area the wind passes. Its not the roundness per se that is making the difference. Its the more efficient use of surface area. Round house does use less surface area per given volume.

If you take a given surface area, and make it round, its still going to receive the same amount of force.

So I guess I have to agree. Given a fixed square footage (2400) which yields a fixed volume, the round house will be affected less by the wind pressure because it will have less surface area.

[SJF]

The cited article is nothing more than a sales pitch -- a simple answer to a very complex question. A structure, whatever its shape, should be designed to resist whatever forces may be imposed, windwise or otherwise. The shape of the structure is only one of many factors to be considered in design, factors such as esthetics, economy, utility and the desire to have something unique. Considering these, it is easy to see why circular and dome houses have not become a standard.

For an indication of how complex innovative design to resist wind stresses can be --

SJF

[Edwin Pawlowski]

Circular is far from the "best" overall design, but it can be a style to be admired by some. It has plenty of drawbacks from a practicality point of view. But if you have the money . . . .

If you want to build for strength, I'd go with concrete. Using insulating concrete forms is becoming very popular both because of the strength issues and the energy efficiency.

are just a few of them. I saw pictures of one that went through a tornado. While there was some damage, the interior was hardly touched.