Building materials in tornado/hurricane areas (U.S.)

Why are house in many/most areaa of the U.S. that are hit by hurricanes or tornadoes made of wood or other weak materials?
I imagine there’s a cost issue, but insurance for a brick-and-mortar house would be significantly less.

I am certainly no expert and have no cites, but wouldn’t even a brick and mortar house get severely damaged in a hurricane or decent tornado?

On what basis do you say this? I actually surveyed three insurance companies (SAFECo, State Farm, and Farmer’s) recently who told me there was absolutely no difference in insurance cost for wood versus brick, even in terms of fire insurance.

On no basis at all, simply that if there is something like tornado insurance I’d guess that a “solider” house would have better chances of survival and therefore lower insurance.
I may be completely wrong.

I think the part you’re not accounting for is that most of the real destruction in hurricanes comes from storm surge flooding, and to a lesser extent rainwater flooding.

Wind does do some damage, but generally speaking, it’s the storm surge that does the real damage.

Cinder blocks, wood, etc… very little short of a reinforced concrete bunker is going to withstand storm surge, and it’ll be flooded anyway.

You may be interested in FEMA Publication 549 which deals in part with building performance during Hurricane Katrina.

Yes - depending upon the home construction a relatively “mild” severe wind can cause serious damage or even destroy a house. One common situation in the midwest is where the shingles start to lift off the roof at about 60-80mph, and then the wind gets into the attic and pushes the walls out from the inside, unwrapping the roof. After the roof is gone, then the walls below sometimes have greatly reduced strength, and they can literally start falling like dominoes.

Another thing which happens is when the shingles hold (such as, you paid extra for the 130-mph-rated GAF-ELK shingles) and the entire roof comes off, because of course the builders didn’t spend the incredibly small amount of money to tie the roof securely to the walls below with steel straps or bolts. Repeat the above scenario.

In Florida in the 1990’s there was a serious issue noted by Engineers where houses which were designed to be “hurricane ready” were in fact ready, until the wind blew in the garage doors. Once the wind pressure hit the inside, the garage walls and ceiling would give way, and in some cases this would start a cascade failure of the house. I saw photos from a report of several neighbourhoods where every single house which had an intact garage door was standing, and every house which had the garage door fail was destroyed. I knew an Engineer who analyzed the doors with a crude FEA program called “ANSYS” at the time, and he found that just $10 more of steel per door (about $50 installed) could have saved people’s entire $300k homes in that situation. On that note, a lot of homeowners really do forget about the huge frontal area taken up by their garage doors, and get the cheapest possible weak-ass doors that will fold under a 60-mph gust.

You might want to look up Mike Holmes’ work with Brad Pitt in bringing back the Ninth Ward in New Orleans. They’re building wooden homes on stilts. The homes will survive most hurricane winds and the stilts keep them above the storm surge.

Most “brick” homes in the US are brick veneer construction, where the brick is basically a siding over a traditional stick built frame. They may look more solid, but in this case the brick provides about zero added strength.

Even structural double brick wall is weak in ways that a simple wood frame wall isn’t. Different materials have their advantages and disadvantages.

Changes in building methods and code over the years are often not intuitive and are the result of experiment and observation. Sometimes, as Una mentions fairly simple changes can result in great improvements.

I’d like to point out that an F4 tornado, much less an F5, is capable of scouring even a brick house down to its foundations. Fortunately, most tornadoes aren’t that strong, but it does become a cost-effectiveness issue - you might want to pay to build a house that can handle an F1 or even an F2 but maybe not an F5 (if that’s even possible - build a good basement for that one) as they aren’t common and it would certainly drive up the expense a great deal.

As also point out, a lot of the collapses begin when a roof departs the structure. Having brick walls doesn’t help that much when the roof comes off and a tornado vacuums up the contents of your home (possibly including you) then you get water damage from the rest of the storm system. Sure, you sort of have half a house standing, but it may still be a complete write off due to damage to the structure.

I have been around numerous post-tornadic destructions, and almost always its the roof damage that happens initially with the rest of structure ‘collapsing’ (or being relocated forcibly) afterwards if winds persist long enough. Its kinda rare to have just wall damage (of major proportion anyways) from tornadic winds, ime. I watch all too often in Springtimes the usual viewed-from-helicopter reporting that is seemingly mandatory for Oklahoma news-stations and usually the pilot flies along the path of ‘disappeared’ roofs with occasional debris from other parts of structures. I knew one guy who lost his roof, twice (separate storms, one being the massive Moore F5) with little other damage to walls/interior. Two different towns, too (funny in hindsight how he gets chased around the state by weather!). Just plucked his roof(s) off and carried ‘em elsewhere. Fortunately, he and wife/kiddo were elsewhere as it is easy to figure out if the path is coming towards you. (Oklahoma weather-radar/storm-chasers rock!!!) The first time it happened to him, he told me he was eerily surprised how practically nothing inside the house even moved from where it was, including bedsheets remaining upon mattresses and all pics still hanging on walls. Same thing with other neighbors around him for the most part, too. Some of the houses were damaged from blowing/falling debris (or neighbors’ roofs!), of course, and neither material will withstand such forces applied to them.

Also, I often see entire brick walls fallen in one big/long piece whereas wooden walls will lose a bit here and there rather than come apart in one connected chunk, so to speak. The building can explode if the roof stays on and structure pressurizes, or vice-versa with implosion (looks cool on video, but no fun if nearby, of course).

Pros and cons to both materials, of course, and I don’t see, by my eyes, any real thing that makes one hugely favorable over the other (brick-v-wood). Not here in Oklahoma anyways. ymmv

6-8-1974, Tulsa Oklahoma.

Lots of tornadoes that night and they were hiding in the rain.

It is not always easy to get out of the way then.

Myself, 4 year old son & 1 year old daughter were inside the house.

When bricks and boards fly through a rock wall, 3 interior walls and are embedded in the last rock wall in the back of the house, the pictures that are still hanging on the wall do not give you much confidence about how weak a tornado is or isn’t.

The one that hit us was not on the ground cleaning off slabs, that was December of 1975 and ½ mile S/E of us. Ours was about 6’ off the ground judging by personal observation. Up close & real personal. The tornado slammed the closet door shut, it could just as easily yanked it out of my hand.

It all comes down to money. What are the odds? My son built his new house with a strong room in the basement. Prolly safe from any tornado, if he & family can got to it. Lots of storm cellars around tornado alley, even in some fancy additions. They are not insanely expensive to add to older places.

I have not built one here. I might be killed by a tornado some day but much more likely to be killed by you making a left turn right in front of me while I ride my motorcycle.

All about risk management & personal choice …

YMMV :smiley:

Well, my brick house (in a not-tornado/hurricane but earthquake-prone area) is cement, brick, and reinforcing rebars. The “frame” is cement and rebars. If wind can blow it away, I’ll stop worrying for it is clearly the end of the world.

But what is the roof made from? If the walls are still standing but the interior is flooded out and ruined, there isn’t much difference for the insurance company.

Wolf insurance, on the other hand, is lower for brick houses than houses made of wood or straw.

Browse the photos of the St. Louis cyclone of 1896. In those days, brick houses were really brick. And it didn’t make any difference in roofs being torn off – and not really any difference in walls being knocked down.

The first page of the web site notes that the city’s public hospital (an old fortress of a building) and Eads Bridge were both damaged by the twister, and they’re both a damn sight sturdier than any house.

Roof is cement and rebars.