MR. KOJO NNAMDIFrom WAMU 88.5 at American University in Washington, welcome to "The Kojo Nnamdi Show," connecting your neighborhood with the world. Roger Lewis is here. In a city that bristles at government regulation, the mayor of Moore, Okla. said yesterday it's time for a new law, one that requires storm shelters or safe rooms in newly-built homes. The deadly tornado that decimated houses and schools on Monday has prompted new questions about safety.

MR. KOJO NNAMDIWhy don't more homes in that stretch of tornado alley have basements or storm cellars or some place to take shelter from violent weather? Why did the elementary school where seven children died have no safe room to protect them? Here in the Washington region, we can't help but wonder how solid our own homes and schools are and how well they can withstand an unexpectedly fierce storm.

MR. KOJO NNAMDIOur area sits, thankfully, outside the worst danger zones for tornados and hurricanes, but recent years have brought us a derecho and an earthquake, along with intense seasonal weather. So what makes a house sturdy enough to stand up to the forces of nature, and when should the government get involved and making sure it does? Here to help us answer these questions is Roger Lewis. He's an architect who writes the "Shaping the City" column for The Washington Post. He's also professor emeritus of architecture at the University of Maryland College Park. Hi, Roger. How is it going?

MR. ROGER LEWISWell, it's going. Our house is still standing. I'm happy to report that.

NNAMDINot so for so many people's...

LEWISNo.

NNAMDI...homes in Moore, Okla.

LEWISIt's just awful to read the story.

NNAMDIThe website for that city recommends that homes have a storm safe room or an underground cellar, but the city does not require them and estimates that only about 10 percent of homes have them. What role should the government play in requiring safety measures in case of deadly storm?

LEWISWell, there's a long history, of course, of governments requiring their construction meet safety standards. I mean there's really a constitutional justification for that, how safety and welfare -- building codes which in this country are extensive -- there are both national and international codes -- are written primarily for the purpose of ensuring that when buildings are built that people will be safe, that they -- and most of the codes anticipate the usual threats you might expect. I wrote down here, earth, wind and fire.

NNAMDIIt sounds like the name of a group, yeah.

LEWISI think is the name of a rock group, yes, yes. But there -- these codes address exactly the issue of -- and certain zone where earthquakes are likely, you have to design and construct buildings that are capable of resisting, up to a point, earthquake. And the same is true in Florida for hurricane -- potential hurricane damage.

LEWISSo we have -- we don't have to reinvent the wheel in terms of justifying the notion of having government -- having the public really, say, look, we want buildings, particularly public buildings, not just private buildings, but public buildings to be safe given all the risks. And probably the one that is most commonly understood is fire and smoke, the -- all the things we do unbelievable number of things we do to make sure people don't suffer from fire.

NNAMDIIf you'd like to join the conversation, give us a call at 800-433-8850. What part of your house is more vulnerable to wind or water damage in a big storm? Should local building codes require safety features in homes and schools to protect people in case of, well, unlikely but potentially devastating storms? 800-433-8850.

NNAMDIYou can send email to kojo@wamu.org or send us a tweet, @kojoshow. Since the tornado hit Oklahoma on Monday, a lot of people have asked why there aren't more basements and storm cellars in the state. Some experts blame the clay soil and the high water table. But do those geological features make it hard to build basements?

LEWISWell, this has been greatly exaggerated. There's no question that in every location and locality -- where I grew up in Houston, for example, in -- on the Gulf Coast, which is an alluvial plain, very few houses have basements, not because they can't build them, but that there's been no reason to build them. It's -- you don't have to worry about frost heaving. You can build a shallow foundation. The house will usually stay there. There are -- we'll come back to that. I want to answer the question by going to the word unlikely that you used a moment ago.

NNAMDIYes.

LEWISThis is all about probabilities, but the old codes, old codes, all the quantitative specifications or limits are essentially probabilistic. That is we are asked to design and construct buildings that that will with an acceptable level of risk but is -- it does not reduce the risks to zero. None of the codes will take the risks to zero. And I think that in the case of the conditions in Oklahoma, you have people living there, they're gambling.

LEWISThey're gambling. They're saying, well, I can't afford this house. If I build a basement or if I have to spend four or five or $6,000 on some kind of shelter, I'm willing to take a risk that no tornado is going to be knocking at my door. And it is a risk. It's a gamble. And some people lose the gamble. The question is, what -- at what point do you say, well, the risk is great enough just as we have done with -- for fire- and earthquake-prone areas, at what point do you say no, no? This is no longer -- the risk is no longer inconsequential. It's time to take steps, particularly for places like schools.

LEWISAnd I would be the first to suggest that there are ways of building shelters. We don't -- they don't have to necessarily be traditional basements. There are -- you want to be underground. You could be in some kind of prefabricated structure or structures that are set into the ground. You can even build safe rooms. I think we've heard a lot about safe rooms. You can build aboveground if the structure of that, including its anchorage to the earth, sufficient to keep it in place during a tornado.

NNAMDIWell, in the aftermath of the storm, there are lots of questions about whose job it is to protect people. Should the government set the safety standards for new houses, or should the housing market set or drive the decisions? There was one president -- former president of the Oklahoma State Home Builders Association who says, look, most home builders would be against the government requiring safe rooms in homes because we think the market ought to drive what people are putting in houses, not the government.

NNAMDIThere is a significant amount of resistance to what some people would call government intervention in the form of regulation about how they should build their homes.

LEWISWell, particularly in places like Texas and Oklahoma.

NNAMDIExactly.

LEWISNo, no. I mean I -- there is a kind of sociological, economic, philosophical dimension to this discussion because there's no question that people in places like Moore, Okla., or where I grew up, they have a kind of ideological resistance to the notion of being told how they should build. The problem, again, is that the way you build can affect people who aren't necessarily involved in the decision made about how to build, like the hundreds of schoolchildren in the building or your neighbors.

LEWISAnd one of the things people should remember is one of the great threats during a tornado is not just the collapse of structures but the incredible debris that's flying around at -- basically shrapnel. I mean it's a war zone in a literal way, not just in the aftermath with all this stuff flying around. And even if your building stands up, the glass and the windows, the elements that get torn off of the neighbor's roof can come flying into your house. So it's nice to know your neighbor's house isn't going to explode and shrapnel come into your house.

NNAMDI800-433-8850. What part of your house would you take shelter in during a hurricane or a tornado? 800-433-8850. You can send email to kojo@wamu.org or send us a tweet, @kojoshow. You can go to our website, kojoshow.org, and join the conversation there. Here is Joe in Damascus, Md. Joe, you're on the air. Go ahead, please.

JOEThank you. It's a pleasure to be on. One of my problems after being a builder for 35 years is that entrenched interests seem to drive our industry rather than often time commonsense, such as a sprinkler systems in every single house that have to add 12- to $15,000 on the homes I build versus maybe fire code drywall.

JOEAnd I wonder what entrenched interest will drive these building codes when simple alternatives like an all-block home, concrete masonry unit home rather than home so that at least the debris when it hits, if it's of the block are poured with concrete and rebar, it would seem that that would stand up much better. And I do agree with your guest that if the safe rooms even on the ground floor are anchored to the ground in some way that I can not understand how any type of safe room would ever venture to be eight or $10,000.

NNAMDIOK, Roger Lewis.

LEWISWell, I think I understand exactly where he's coming from, and just in -- during my career, I've seen the codes become more stringent. When I first started practice, no one put sprinkler systems in single-family houses. There are a number of jurisdictions in the United States where you have to provide sprinkler systems.

NNAMDIRequire them.

LEWISThat's required. I mean, it's -- I think the, you know, we can build -- I think what he's saying -- and I agree with it -- we could build houses in Oklahoma not necessarily with concrete mason blocks, but you pour the concrete, reinforced concrete, and if it's made, if it's done correctly -- not like they've done it in Silver Spring in that transportation building -- if the concrete is properly reinforced with steel, you could build a building in Oklahoma that would withstand a tornado.

LEWISIt would look completely different from the houses that are built there. It would cost more. It would -- it gets back to your market point, Kojo. The market wouldn't support right -- as it exists now, the market wouldn't pay for or the people who are in the market couldn't afford the kind of house that our caller is describing, unless they're willing to live in a much smaller house.

LEWISI mean, there are things that -- you know, there are tradeoffs when we build or design houses. And, you know, if you want an 1,800 or a 2,000-square-foot house in Oklahoma and you can only afford $2,000 a month, it's going to be wood frame. It's, you know, it's just not going to be made with concrete masonry units and poured-in-place concrete. It's -- but you...

NNAMDIYou say it drives the Europeans crazy, the (unintelligible) ?

LEWISOh, yeah, we've talked about that before, yeah. The -- when Europeans come here, they're just -- they're astounded that we build houses with two-by-fours and nail guns and gusset plates holding trusses together that can easily be torn apart, plywood. All of that is totally foreign to most Europeans. But they have a different tradition. I mean, they -- when they build a house, they're not thinking about it lasting for 25, 30, 35 years till the mortgage is paid off. They want it there for their great-great-great-grandchildren.

NNAMDI800-433-8850 is the number. Joe, thank you very much for your call. We move on now to Gera (sp?) in Alexandria, Va. Gera, you're on the air. Go ahead, please.

GERAThank you, Kojo. I just wanted to say when I was a child, we lived in Oklahoma. And we rented a house, and we were in a tornado area. The house was older, and it was a quite a while ago. But the basement of the house was fully equipped with a refrigerator, a stove, a television set, beds, food, everything. And when tornadoes came through, we went down there, and we wouldn't even hear the tornado. When we came up in the next morning, we'd see cars all over the place in other people's yards, but we were fine.

NNAMDIWell, I'm glad you brought that up because, Roger Lewis, some people say that what it probably cost Gera's family to do that, the cost of building a basement or a storm cellar in Oklahoma's clay soil is prohibitive. Why is it so expensive?

LEWISWell, it's -- what I've read -- and I don't know the condition there although we here have a lot of clay soil in D.C. -- that clays -- clay soil can absorb moisture and expand, loses the moisture, dries out, it contracts, which exerts forces on any structure that's in the ground that you might not have with better drained, more stable soil. But engineering -- you can engineer a structure to deal with that. First of all, people should remember you don't have to have a full basement.

LEWISTo have a place to shelter, you can get a pretty big family in a room that's 8-by-10 feet. So one of the things that they could easily do down there, in my opinion -- or they could've done -- is probably put into the ground reinforced concrete, not block, a reinforced concrete structure. And part of the trick is also making sure the ceiling of that structure is not just 2-by-6s with plywood on top.

LEWISBut the cost of building that is a lot less than building a full basement. My guess is that if engineering -- if people had wanted to do this, they would have found ways, I think, to make it affordable and to make it effective without building a full basement. I mean, you could easily build a shelter large enough for most families at reasonably -- affordably.

LEWISThe other thing that occurred to me, which no one has -- maybe there's been some press on this in the last 48 hours, I've often wonder why, you know, neighborhoods -- if you got a block with 20 or 30 houses, you know, you could probably build a, you know, a neighborhood shelter, which you get to within five minutes. Usually, they have more than that as a warning, so that's -- you could communally shelter a sub-neighborhood area in some kind of a structure, again, that's underground or that's...

NNAMDIWhere an increasing number of communities are doing that, as a matter of fact. Gera, thank you very much for your call. We've got to take a short break. But if you have called, stay on the line. We will get to your call. If you haven't yet, the number is 800-433-8850. Has your home or office been badly damaged in any of the big storms in our area? Give us a call, 800-433-8850, or send email to kojo@wamu.org. I'm Kojo Nnamdi.

NNAMDIWelcome back. Roger Lewis joins us to talk about how we build buildings that can withstand the force of nature. He is an architect and columnist with the "Shaping the City" column for The Washington Post. He's also professor emeritus of architecture at the University of Maryland College Park. We're inviting your calls at 800-433-8850. Before I go to the phones, Roger, and before I come to the Washington region, at one of the Oklahoma schools hit by the tornado, children and teachers survived by huddling in the bathroom. Why can a bathroom be stronger than the rest of the building?

LEWISWhy can't it be?

NNAMDIWhy -- how is it that is was stronger?

LEWISWell, I don't know exactly how it was built. It may well have had ceramic tile masonry, concrete block walls rather than stud and gypsum board walls with tile. So you've got higher mass. You got more density there. So it's -- and if they've got horizontal steel reinforcing in the wall, it will stand up much longer than a wood frame partition will. The other thing is the bathrooms tend to be interior as opposed to being near the exterior.

LEWISSo even in many houses, the bathroom is one of the places -- especially if it's got a bathtub, where you can get inside the bathtub. Those are safer -- relatively safer. It would not be a lot more money to actually, again, build the bathroom in the middle of a school with not block, but reinforced concrete walls. You know, it's -- plus, you have also cavity walls where the plumbing is because you have to have a place to run the pipes that are in walls. Those are often double walls. So that is the logical thing.

LEWISThat would be the -- my first thought, if I ran a school, would be to head into the middle of the building and preferably into a bathroom. There is just more stuff around me. And I think one of the kids pointed out, as I recollect, some of them were able to shelter by getting under toilet and lavatory fixtures, that the fixtures themselves, which are anchored usually very firmly to the substructure, can provide some degree of safety.

NNAMDIHere in the Washington region, we don't get many tornadoes, even though we do get a few. And when we do, however, they are usually in the weaker category. What do our local building codes say about withstanding strong winds?

LEWISWell, winds are in the handbooks that tell engineers how to design structures. They stipulate wind loads that are nowhere near tornadic velocity. So our buildings generally have been designed, have been engineered to withstand winds between 100 and 150 miles an hour. Probably in reality, they would start being ineffective.

LEWISThe building would start coming apart at 120- or 130-mile-an-hour winds, hurricane-force winds. There -- the problem with the tornado is not just the velocity of the wind, but it's the rotation. It's the fact that the wind -- unlike the derecho that come though here last year which is where the winds are straight.

NNAMDII was about to ask about that.

LEWISAnd when -- if the wind is staying straight, even in a very high wind, a structure will deform a bit. But it will deform in just one way. It'll just -- it'll deform in the direction the wind is blowing it. You get tornadic spinning action, and that is far more dangerous because it's putting -- it's constantly changing the direction of forces, the stresses and strains in the structural elements.

LEWISAnd you could start tearing apart connectors. I mean, it's far more dangerous. I think here, we're OK. We can stand -- I think most of our buildings will do just fine in most wind conditions, in hurricane conditions. A lot of them would be very susceptible to a tornado.

NNAMDIWell, Richard in Alexandria, Va. doesn't seem to think we're that OK. Richard, you're on the air. Go ahead, please.

RICHARDHi, Roger. I was a year ahead of you at MIT. Richard Titus (sp?) is the last name.

LEWISHi, Richard.

RICHARDWe're talking about -- in this area, we're going up now as high as six-story apartment houses with stick and dry wall, and I'm wondering how they'll perform in serious wind loads.

LEWISA fair question. Actually, under the code, you -- most of the buildings you see that are going up six stories, the -- usually, the first two stories are not stick-built. What -- we just had one put up right next to the University of Maryland campus, a quite ugly building, I might add, but that's another story. They -- the first two floors are actually reinforced concrete frame. The skeleton is not wood frame. And then the four floors above that are wood frame.

LEWISAnd that's -- that is possible because under the codes, you can go as high as four floors with conventional stick-built framing. It's done because it's cheaper, and I think you're absolutely right, Richard, that, even with the bottom two floors framed in concrete, we know wind velocities increase with altitude. I do think they are more vulnerable. I think there's no question that the tornado that came across the Maryland campus a few years ago, the north side of the campus, killed two sisters, picked their car up and just threw it right over one of the dormitories.

LEWISIf that tornado hit this building I'm talking about that's under construction not far from our school of architecture, there could be serious damage. What people should remember is what happens in a tornado, and to some extent a hurricane is it -- when it hits, whatever is most vulnerable disappears first, pulls the roofing tiles and the roofing shingles off.

LEWISThe plywood start -- there's a lot of uplift force, tears off the plywood sheathing. Now you have exposed the trusses or the roof rafters. They immediately get torn off. I mean, it's -- it happens very quickly. But once you've got the roof gone and the winds are whipping around and getting into the building and laterally putting force on these partitions that are just 2-by-4s, or even metal studs, it's going to come apart.

NNAMDIRichard, thank you very much for your call. Roger, what are some of the other natural threats to buildings here in our area, flooding, settling, termites?

LEWISYeah. I'm mean, you're getting them, certainly trees. Almost every storm we have with wind, I mean, I -- seems to me that almost every time there's a news clip about showing a tree that's come over and hit a car or house or chopped the house in two, limbs can come flying off again. They're missiles. They can -- I don't think we have too much risk of an entire building being shredded the way we saw Moore -- the houses in Moore shredded, but I think with this -- our tree cover is wonderful.

LEWISBut you got to keep at them, trimming them, getting rid of dead branches and so forth. I think that's a risk. Certainly, we now know we can have earthquakes. We're in -- if we had a serious earthquake of the sort that have hit some -- that we've seen in places -- other places in the world and even out in California, again, a lot of our buildings would be seriously damaged, I think.

NNAMDIOn to Ken in Gaithersburg, Md. Ken, your turn.

KENYes, thank you. I have a comment which is this: I grew up in Taiwan, which is prone to typhoons and earthquakes and flooding and all manner of pestilence, and I'm struck by how Pollyanna the assumptions are here as far as the strength in building, both in Maryland, in D.C. and, I'm assuming, Virginia. The sort of weather that we get and that we're due to be getting seems to me to produce outsized damage and catastrophes.

KENWhen we had a hurricane go through here about 10 years ago, Montgomery County was closed out for almost two weeks. We get far more severe weather in Taipei. The buildings are built out of reinforced concrete, fairly inexpensively. And a typhoon runs through, and we're back to business the next day. I -- it astounds me.

NNAMDIOur assumptions here, Ken says, are way too optimistic.

LEWISWell, and I think it's interesting. It's all, again, probability. We're taking a risk. We're taking -- we're gambling that we're not going to have forces that exceed the forces the engineers have designed buildings to withstand. He brings up the issue of climate change, though, implicitly in his comment, that there's been a lot of speculation. Are we seeing more powerful, more frequent, perhaps, weather patterns and conditions that might sponsor or might motivate us to rethink the standards? You know, maybe we do need to rethink what we're -- how our engineering abilities in terms of resisting wind.

LEWISAnd by the way, the other thing I've -- in terms of natural threats, we should not forget moisture, not just rain but the moisture and wood rotting and mildew. I mean, there's, you know, there are a whole bunch of things you need to worry about when you build buildings. But I think climate change is certainly something we're going to have to take a look at more thoroughly in terms of the codes that are response to climatic loads.

NNAMDIKen, thank you for your call. One building official in Moore, Okla. said you can't build a structure that would take a direct hit from a mile-wide tornado and still be standing. You've said, Roger, that it's possible, but it wouldn't be pretty or affordable. What would tornado-resistant house look like?

LEWISWell, I've -- you know what? I think what we would have to say is you'd have probably something that is sort of viametrically compact. It might be spherically or cubically shaped. It might be -- think of an igloo made out of reinforced concrete, a large igloo well-anchored to the earth with very small windows, with extremely strong glass.

NNAMDIYeah.

LEWISBy the way, glass is very strong. You can easily have glass that will resist 200-mile-hour winds. We have it on airplanes. No, you can build a house -- you can build an above-ground house, but it wouldn't look anything like the houses in Moore, Okla. or, for that matter, Washington, D.C. It would be low to the ground. It would have a few spoilers that projected out from it so that the uplift -- when you get wind going across the surface of almost anything, it actually creates uplift, the same lift force that you get on an airplane wing.

LEWISAnd you can spoil that. You can have things as you see them on race cars. You can have vanes anchored very securely to it that will cause eddies, that we'll turbulence. And that turbulence defeats the uplift. We could sit -- I -- with a good engineer, I could sit down and design a house that would withstand a tornado, but I don't think we could sell it.

NNAMDIOK. Here then is Mike in Severn, Md. Mike, you're on the air. Go ahead, please.

MIKEHi. I just wanted to tell a personal story. We experienced a very small tornado, came right through our court and destroyed a ton of trees. And some of the property around it was damaged. It was very scary. We had a six-month-old at the time. Well, here we are 18 years later. He's getting ready to go to College Park.

MIKEAnd he'll be attending partially because of the scholarship that was formed in the memory of the two girls that you just mentioned that perished in a tornado there. So it's just kind of ironic that we lived through one, and now he's going to go to college because of, you know, how it affected another family. I did want to ask a question.

NNAMDISure.

MIKEWhat are your expectations in terms of the extreme weather and kind of the possibility of Maryland, D.C., Virginia getting hit with something that's going to be more than, you know, an EF1, EF2, EF3?

NNAMDIRoger is not a climatology expert, but I think we could...

LEWISNo. I wish I had -- I designed a house some years back for the man who was chair of our department of meteorology. I wish he were -- if he's listening, I hope he would call, Ford Bayer (sp?). He can answer that question. I don't know the answer to that. I do think that whenever these events happen, though, it makes us stop and think. You know, are we doing as good a job as we can do or should do in terms of making sure people are safe in the built environment?

NNAMDIAnd the only thing, I think, we can expect, Mike, is the unexpected. That's what seems to be on the horizon, though.

LEWISWe should say, again, tornadoes -- there's no question with tornadoes. They really like flat land. So there, you know, we're lucky in a way. We are in a region what -- there definitely areas of this -- that are susceptible in Virginia and Maryland because there is a lot -- there is sufficient amount of flat land. But there's not anywhere the kind of distance and expanse that we see in the Midwest. I mean, there -- so our risk is, I think, we'll never be anywhere close to the risk in the Midwest.

NNAMDIMike, thank you very much for your call. We got an email from Lexi, who says, "My question is this: If the town and state are so opposed to government intervention, that they are willing to gamble with citizens' lives, shouldn't they be barred from receiving government funding to rebuild? This is a teachable moment to show that the government's role is most useful when it is preventive, not after lives are lost and the clean up is necessary.

NNAMDII'll also point out that the senator from Oklahoma who voted against Sandy relief now wants the rest of the country to aid his state." That would be Sen. Jin Inhofe. Is that how his name is pronounced?

LEWISI think that's right. I read that piece yesterday in The Washington Post or The New York Times. Yeah, I mean, it's -- we get -- you get into the politics here. I don't think we want to turn this into The Politics Hour but there's...

NNAMDIThank you very much, but go ahead.

LEWISWell, there's no question that there -- this behavior in Oklahoma, this resistance to trying -- mandating that safeguards be taken is in part a political issue. It's an economic issue, but it's also a political issue. At the top of the hour, we talked about the sort of resistance, the ideological resistance in places like that to having a government stipulate how you build your building.

LEWISIt is a little bit hypocritical. I mean, the word hypocrisy comes to mind when these senators -- as I understand, the Oklahoma delegation, the majority of the delegation in Congress voted against money for the victims of Sandy, if I got this right. And then now, of course, they're turning around and saying, oh, but, you know, maybe we ought to get some help from the federal government.

NNAMDIYes. That's the way it's certainly been reported in the news. We got another email from Linda in Rockville: "When we lived in Florida, we needed to buy hurricane insurance. When we lived in Pennsylvania, our house was in a flood zone, and we needed to buy flood insurance. Is there any tornado insurance, especially for houses in Tornado Alley, that you know of?"

LEWISWell, that -- yeah. I think there is insurance. I don't know -- we talked about that on the phone a couple of days ago, your producer and I. I think -- I don't know exactly how the policies are written down there. You know, this is an act of God. This is an act of nature. And my guess is that there is probably some provision. Whether it would cover anywhere near the losses they have experienced, I don't know.

LEWISI think that one of the questions that the insurance question raises is whether either the private companies or the government should be writing in insurance in places where there's -- where there are these risks. I mean, we -- every year, there's flooding in the Mississippi Valley, in places that -- I think we've talked about this before on the show -- where people come back, build a house and get swept away again, and they come back and -- you know, these are...

NNAMDIYou have said that there are places in New Orleans...

LEWISWe shouldn't build.

NNAMDI...in which we should not be rebuilding after Hurricane Katrina. OK. Here's -- is Yann (sp?) in Alexandria, Va. Hi, Yann.

YANNHello. Good afternoon.

NNAMDIGood afternoon.

YANNDedicated listener here. I would identify myself as what your guest described as one of the bewildered Europeans living in the United States, with the addition that my wife and my wife's family is largely from Oklahoma. So I take a keen interest in this topic. My specific question is about insulated concrete forms. A few years ago, I found myself going to the World of Concrete trade show in Las Vegas.

YANNAnd I went to a presentation by part of the concrete industry that's dedicated to building -- to this new technology called -- or relatively new technology called insulated concrete forms. If you imagine Lego pieces made of Styrofoam out of which you basically make the shell of a house, and then you pour concrete into this hollow -- then you end up with a concrete house.

NNAMDIOK. Got the picture.

YANNApparently, based on the -- on this industry data, residential houses built that way can be only 20 percent more expensive than wood-frame houses. So I was wondering if your guest could comment on the statistics and whether this would be an alternative new standard in residential housing construction.

NNAMDIRoger?

LEWISWell, as I said earlier, there's no question we can build houses or other buildings that are much better at resisting the forces of nature. And you mentioned one system there. There are some others. I think the key here is when you say 20 percent more expensive, that still drives the train. The fact is what is -- what most homebuilders are doing is that they look at a market, and they say, well, this is a market that people out here that I'm going to sell to can afford, X-thousand dollars a month and so many dollars of down payment.

LEWISAnd then they build an economic model in which they look at how inexpensively they can deliver the product that they know those people can buy. And, I mean, what I'm doing is describing the process that is very fundamental to the way residential real estate is developed. And they're not going to build using this system if it's 20 percent more expensive unless they believe they can get 24 -- 20 percent more, whatever the number is, in dollars when they go to market, and given also comparability.

LEWISThere's -- there are other factors. I mean, there's -- there are cultural factors. People like houses that look like their grandmother's house, or they like houses that don't look like they're concrete bunkers. I -- it's a topic maybe for another show when we talk about building systems 'cause there are other ways to build. But, again, you're never -- you cannot build a house more cheaply still than 2 by 4, 16 inches on center.

NNAMDIYann, thank you very much for your call. We're going to take a short break. We're still taking your calls at 800-433-8850. What part of your house is most vulnerable to wind or water damage in a big storm? What part of your house would you take shelter in during a hurricane or tornado? Give us a call, 800-433-8850. I'm Kojo Nnamdi.

NNAMDIWelcome back. We're talking with Roger Lewis about building buildings that withstand the force of nature. Roger Lewis is an architect and a "Shaping the City" columnist for The Washington Post. He's professor emeritus of architecture at the University of Maryland, College Park. And in one of the emails I read, one of our emailers said that when they lived in Florida, they had to buy hurricane insurance. Roger, you've designed residence in Florida to withstand hurricanes. What other requirements and current practice is there?

LEWISYeah. They require that -- or the key things. They require that roofs and walls be tied together, be connected in ways that make it difficult for the winds to pull the roof off, because, again, as I said earlier, once you tear the roof off, you're finished. The -- they also anticipate storm surge, flooding. And in many areas of Florida, particularly near the coast, you can't -- you have to elevate the first habitable floor level so that it's above any expected rise in the water.

LEWISThat doesn't mean that it can't be exceeded. If there was a serious tsunami that hit the Florida coast, a lot of buildings would be in serious trouble. But the buildings I designed in the '90s down in Vero Beach, for example, we -- the roof structures are strapped down. The connection of framing to the footings, all of that is tied together in ways that we don't do -- we don't do it here.

LEWISWe don't tie them together as -- we probably should tie them because it's good practice anyway. But that's the main thing that the hurricane code requires it. There are some other specifications about windows. I don't want to get too technical here, but you can't use just any window. The windows are -- that are blessed for hurricane resistance are also somewhat special.

NNAMDICan you retrofit or reinforce an existing building to stand up better to extreme wind?

LEWISYeah, yeah. Yeah, you could. For example, right now in California, they're doing that for earthquake resistance with a lot of very large buildings. They're going in and putting additional bracing and structural members that will allow them to stand up to earthquake forces. Yes, you can retrofit buildings.

NNAMDIHere's Catherine in Washington, D.C. Catherine, you're on the air. Go ahead, please.

CATHERINEYes, please. Why isn't anyone talking about Buckminster Fuller's geodesic dome? I just don't understand it. It's like they have blinders on where that science or that technology is concerned. He was so far ahead of his time, and it's like we just don't want to go there. It's like, you know, Exxon not wanting to go with solar energy. I just don't understand it. That's my question.

NNAMDIWell, Catherine, you should know we got a tweet from Joshua, who says, "If the government pays to rebuild, they should mandate concrete geodesic domes." Here's Roger.

LEWISWell, geodesic domes are very familiar to those of us who were students at MIT in the 1960s. They -- I mean, the reason no one's building geodesic domes is, again, the market doesn't want to live in a geodesic dome. I mean, you know, people don't want to live in a geodesic dome. There are other issues, Catherine, that we can't go into here concerning geodesic domes that make them problematic, that are independent of the structural capability.

LEWISI mean, the reason the geodesic dome -- I think the reason you're mentioning it, which is absolutely great, is like an igloo. It is a very, very stable, efficient structure. But turning it into a single-family house or an apartment building or an office building is not easy.

NNAMDIThank you very much for your call, Catherine. We move on to Mary in Alexandria, Va. Mary, your turn.

MARYThanks for taking my call.

NNAMDIYou're welcome.

MARYI was wondering, when FEMA provides assistance for repairing and rebuilding, couldn't there be some condition or incentive that would have the building owners build their -- rebuild or repair more effectively for whatever the area is? And then insurance companies could offer discounts for those structures that were repaired or rebuilt more soundly.

NNAMDII suspect all of that is within the realm of the possible, Mary. Whether or not it's within the realm of the probable is another story.

LEWISYeah. I think Mary's proposal is very sensible, I mean, you know, exactly. I mean, it demonstrates something we haven't talked about, which is that there could be savings. I mean, you could save on your insurance premiums if you've done some things to mitigate risk. And they -- we know they do that for automobile insurance. We know if your house is sprinklered. Most insurance companies will lower the premium for fire insurance. So I think Mary's proposal is quite sensible.

NNAMDIThank you for your call, Mary. We get the opportunity then to go to George in Shepherdstown, W.Va. Hi, George.

GEORGEHi. My comment again was on the evaluation of houses. One of the things that I ran into when I just had an appraisal was that anything underground, no matter its finish or not, doesn't count in the appraisal of the house. And I think also energy-efficient additions to the house and structural reinforcement to the house also doesn't get the value mainly because of Fannie Mae and Freddie Mac's evaluation of what does makes a house worth whatever, dollars.

NNAMDIRoger.

LEWISIt's a very good observation. I think he's right -- I think he spot on. Again, we're talking about the economics of real estate. And basements and garages is also are -- they're included in the appraisal, but they're discounted. The value of a garage or basement space is much less. And he's absolutely right. I think -- for example, appraisers tend to look at a house that's clad with brick and then think it's a little more valuable than a building clad with wood when, in fact, that's actually irrelevant 'cause the brick on houses is veneer.

LEWISIt has no structural -- doesn't do a thing structurally for a house. The -- what make houses stable is the framing and the sheeting that provides the lateral stability. No, no, I think his point is very valid that we essentially -- they count rooms, they count square footage and the general condition, the cosmetic condition. That's counts much more than how structurally a structure is built.

NNAMDIThank you very much for your call, George. Here is Jenny in Frederick, Md. Jenny, you're on the air. Go ahead, please.

JENNYHi. Around here, we've seen reports on TV from a company in Virginia that makes something that they say looks like a shed on your backyard that is very heavy metal and is bolted to a concrete pad. And it's supposed to be tornado proof. Is your guest familiar with this? And does he think it works?

LEWISI'm not -- I'm familiar with the sort of general concept of these prefabricated shelters. This one in particularly, no, I'm not. And this is not something I have designed or specified, so I'm not that familiar with it. But, I mean, again it's -- you've identified another possible thing that someone could have in their backyard. It does require -- the anchorage is very critical.

LEWISNo matter how the capsule, if you will, is made above ground, if it's going to stay there and not go away, it's got to be really well anchored to the ground. You can't just -- I don't think you can just pour a slab, or the slab would have to be thick enough that gravity would keep it right where it is and it -- then it might work.

NNAMDIThank you for your call, Jenny. On to Gretchen in Washington, D.C. Gretchen, your turn.

GRETCHENHi. Good afternoon. I have a question. In Puerto Rico, most housing, regardless of income level, is done with reinforced concrete to withstand the hurricanes, and it does it successfully. I've never known or understood why this is not done in Florida or other places where there are not a lot of temperature variations to affect the concrete, which does tend to expand a little bit, and, you know, it moves. Why is this not done more commonly in the U.S.?

NNAMDIWell, you should know, Gretchen, that Carlos, who emailed us, had even more to say about that. He talked about everything you said in Puerto Rico. He said, "Construction costs in the island are comparable to the U.S. And steel is more expensive due to transportation cost. So cost is not an issue. Insulation is an engineering problem. It has been solved by several methods and added advantage that these houses seldom burn. Finally, there is plenty of evidence that the construction codes in the U.S. are just subpar. Just visit any area hit by a storm to see the evidence."

LEWISYeah. I mean, I think the -- that there is the evidence that the reinforced concrete, the reason it's not used, the reason we're building all these thick-build houses again is purely cost because it -- or at least that's what the builders are saying. And let's face it. You -- it doesn't take a whole lot of skill to get a guy who can cut 2 by 4s and nail them together according to a plan, simple plan.

NNAMDIThank you very much for your call. We got another email from someone who wants to be -- who is interested in an earth-bermed home. What are earth-bermed homes?

LEWISWell, there are -- there was a period, 30 or 40 years ago, when this was of great interest to architects partly because earth-bermed homes or homes that were partially in the earth -- that's really what it's all about -- were very energy efficient because of the thermal inertia of the earth. Basically, earth berm -- an earth-bermed home is a home in which the walls are essentially retaining walls, ideally reinforced concrete. You can reinforce other concrete block, but probably the simplest is to have reinforced concrete.

LEWISBut you piled the earth up against the walls. You bury much of the home in the ground, or you put it on the ground. And then you pile up earth next to it, and you create -- the earth insulates. The earth gives some stability. You've got to worry about moisture and water penetration. You don't get nice glass windows and picture, you know, picture -- lovable views of the landscape.

NNAMDIWell...

LEWISWe're not going to be going -- building too many of those either.

NNAMDIYeah. Carolyn in Orlean, Md. says, "Well, while they're not traditional homes, they are beautiful and inexpensive to live them -- live in, but they've never caught on." And according to Roger, they probably won't in the immediate future. Roger Lewis is an architect. He writes the "Shaping the City" column for The Washington Post. He's also professor emeritus of architecture at the University of Maryland College Park. Roger, thank you so much for joining us.

LEWISKojo, thank you. This was very, very stimulating.

NNAMDIAnd thank you all for listening. I'm Kojo Nnamdi.