Wednesday, May 20, 2015

Answer Man: Is My Modular Home Safe in a Storm?

Finally, a reporter for The Citizen-Times in Ashville, NC calling himself the "Answer Man" puts out an article that should get people to realize that off-frame modular is a great option when choosing to build their new home.


Here is the article and link:

Question: On the April 13 Opinions page of the Citizen-Times, it is stated that modular homes are not as safe in violent storms as conventionally built houses. Since I live in a modular home, I am wondering if there is any data to show the safety of these homes during bad weather? Should I leave my home and seek shelter elsewhere when storms come?

My answer: I live in a stick-built home made of Styrofoam, vinyl siding and studs. It's basically a cooler. Want to trade?

Real answer: First of all, I wanted to get the terms as clear as possible, so I sent the question to the Insurance Institute for Business & Home Safety, where spokeswoman Tiffany O'Shea sent me this explanation:

"There are two kinds of manufactured homes being produced in factories throughout the United States," she said. "There are manufactured homes built to the U.S. Housing and Urban Development construction code. These are commonly referred to as 'mobile homes' and are built on a steel chassis with wheels. In most cases, the wheels remain attached after the home is set on piles built using dry-stack concrete blocks (blocks piles that are not reinforced and mortared together)."

"They may be single, double or triple wide (one, two or three units mated together) and are typically held down by straps that go from the chassis or side of the home to earth anchors that are screwed into the ground," O'Shea continued. "These homes are the typical targets for evacuation recommendations when severe weather threatens. The other kind of manufactured homes are usually referred to as modular homes; and that seems to be what you are asking about."

Indeed it is. For that part of the question, she provided an answer from Timothy Reinhold, senior vice president for research and the chief engineer at the institute.

"Modular homes are built to the same building codes and subject to the same inspections as 'site built' homes built in the area where the home is to be sited," Reinhold said. "Modular homes are installed on permanent foundations just like site built homes. In theory, modular homes should be just as strong as site built homes in the same area and because they are built in a factory setting they may be subject to higher quality control measures."

I found a couple of industry website stories online, based on a Federal Emergency Management Agency study, suggesting that modular homes are actually stronger than site built homes, in part because of those factory standards and the need to withstand travel and crane lifts.

I also talked with Matt Stone, Buncombe County's director of Permits & Inspections, who also said modular homes "are built to North Carolina building codes and standards, so all that — floor loads, wind loads — is theoretically compliant to stick built."

Stone noted modulars can come in "on-frame" and "off-frame" models, meaning some are sited on the frame and anchored in a similar way to manufactured homes, while off-frame homes are taken off the frames and typically put on a foundation.

Reinhold touched on this, too.

"Some modular homes, and even some site built homes with crawl spaces are strapped down with relatively long metal straps that are typically loose," he said. "If your home is on piers with long loose metal straps as the only sign of anchorage, your home will likely be more vulnerable to high winds than a site built home that is properly anchored (anchor bolts, plate washers and nuts) to a concrete slab, a reinforced masonry or concrete basement wall, or a reinforced masonry or concrete stem-wall around a crawl space."

All sources noted homes built away from the coastline, where hurricanes occur more frequently, are "generally not designed to withstand particularly high winds and many of them can be significantly damaged by relatively weak tornadoes or storms with wind gusts of 100 mph or higher," as Reinhold said.

If you want to check the quality of your modular home, he suggested checking in the attic to see if the trusses are at a minimum made with full-sized 2x4s (1.5-inch by 3.5-inch), and that the ends of the trusses are connected to the tops of the exterior walls using metal straps. Also, try to identify the line where separate modules are connected together in the attic and in the basement or crawl space and make sure that the modules are bolted together and supported along the mating lines, and check to make sure that the floor system is anchored with bolts, plate washers and nuts to the foundation."

This is the opinion of John Boyle. To submit a question, contact him at 828-232-5847 or jboyle@citizen-times.com. Click here to read the original article.

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