Marvin Haworth walks through a house frame that’s under construction in the Seiter Farms development in Moore, Oklahoma.
“You see these hurricane clips right there? You see one at every rafter in the house. They’re all tied to the wall, so that rafter cannot be pulled loose from the wall,” Haworth says as he points toward the connection between the frame’s walls and roof.
Hurricane clips are metal straps that are often used in construction along the Gulf Coast to keep a roof attached to the walls during a hurricane. And home builders like Haworth are required to use them in Moore as part of the city’s building codes.
“It’s all about connectivity. You’re connecting everything today so that the house doesn’t come apart as easily,” Haworth says.
On May 20, 2013, a monster EF5 tornado devastated this community, killing 24 people, including 7 children at Plaza Towers Elementary School. It was the city’s fourth major tornado since 1999.
In 2014, Moore became the only municipality in Oklahoma to adopt residential building codes that are strong enough to survive an EF2 tornado. The new homes in Moore are designed to withstand winds up to 135 miles per hour. The codes require hurricane clips, bolts connecting the frame to the foundation, narrower spaces between roof joists and more durable garage doors, among other things.
Haworth, who helped craft Moore’s codes, says the garage door is the weakest part of a home and is typically the entry point for damage. After a garage door is destroyed, pressure from tornadic winds can take a house apart. First the garage roof fails, followed by the garage walls. The house roof is usually the next to go.
It was apparent following the May 2013 storm that garage doors were the weak link.
“When you went out and looked at them, the houses on the perimeter of that tornado that received the least amount of damage, the garage doors were what was damaged on all of those houses in the outer edges of the tornado,” Haworth said.
Costs of doing business
And those strong garage doors, hurricane clips and other materials come at a cost to builders.
Kevin Simmons, an economist at Austin College in Sherman, Texas, wanted to see if the codes increased the price per square foot per home, hurt new home sales, or influenced the number of permits issued in Moore, as compared to the neighboring city of Norman. What he found surprised him.
“Essentially you saw little to no effect of the building code in terms of the number of homes that are built and sold in Moore,” Simmons said.
When a regulation increases the cost in one market, but not in a neighboring one, Simmons says consumers usually flee in search of lower prices.
“The expectation is that when you increase the building cost, that you may suffer a reduction in sales, you may suffer a reduction in permits,” Simmons said.
But that’s not what happened in Moore. Simmons says that when the codes were initially proposed, engineers expected an increase in cost by about one dollar per square foot. It actually turned out to be about twice that, or even higher in some cases. But home buyers didn’t see a radical change in pricing.
Plus, Simmons says, consumers want stronger houses.
“It reflects a sense on the part of people that live in central Oklahoma that this is a good thing, to have a product, to live in a house, that has a higher probability of surviving a windstorm with little to no damage is something that people demand,” Simmons said.
Florida adopted similar codes statewide after 1992’s Hurricane Andrew. Simmons found those standards reduced windstorm losses by about 72 percent. He believes Oklahoma would also benefit.
“So I think that Oklahoma is a good candidate for doing what the state of Florida did: Enact a statewide building code that's based on these wind engineering principles,” Simmons said.
But not all builders would agree. Tony Faust is the owner of Da Vinci Homes and the president of the Central Oklahoma Home Builders Association. He says all of these new materials are being added behind the walls.
“It's increasing the cost and it just takes time for that appraisal process to catch up and eventually it will show that these homes cost more,” Faust said.
Faust says the cost of constructing a home in Moore has increased by over three dollars per square foot for him. Now, he’s apprehensive about building there.
“If someone contracts us to build a custom home in Moore we will. But as a standard right now, I'm not building speculative homes right now in Moore,” Faust said.
Despite the additional expenses, homebuilder Marvin Haworth says he still thinks the stronger building codes are a good idea.
“Maybe at some point, everybody would want to build their house, whether they live in Moore [or not] they might say, I want that code in my house. I want you to build my house to this code,” Haworth said.
But he would still like to revisit the regulations to bring down some costs.
Support for this article was provided by the Weather Eye Award, an award given to distinguished local reporters by RiseLocal, a project of New America’s National Network.