OMAHA, Neb. -- Tornado-Proof Homes Going Up In Omaha

An Omaha builder is constructing houses that she said stand up to some of strongest tornadoes.

They are called ICF homes, built with concrete. Residents in the metro are starting to request them, said Nancy Tess of Forever Homes.

Storms like Wednesday night's scare Keith Edmonds' wife, he said, especially those that bring high winds and tornadoes.

"It's got to be absolutely safe or she's not going to go for it," Edmond said.

The Edmonds are working with Tess to design the strongest home possible, one that can stand up to 250 mph winds. They'll even create a safe room inside with concrete walls and ceiling and a reinforced steel door.

"I can feel absolutely comfortable you're going to be safe in this house," said Tess.

The homes are built with insulated concrete form blocks that fit together like LEGOs. The hollow core of the block is reinforced with rebar and then filled with concrete once that concrete has cured.

Tess said she started building these ICF homes a few years ago after a desire to build a safer home for her aging parents without the need for a basement.

Now, she's done five of them, including her own.

The ICF homes are also said to be very energy efficient by cutting bills 50 percent.

Tess said they cost about 5 percent more to build.