The Associated Press

LEXINGTON - Severe wind damage to homes across Kentucky has some officials pressing the state to raise its standards for construction of residential roofs.

The state building code, which sets the minimum standards, requires a single family dwelling to be able to withstand a three-second gust of 90 mph winds. Until two years ago, the wind-speed requirement was only 70 mph. An F3 tornado has wind speeds of at least 158 mph.

A May 27 tornado damaged the roofs of about 300 homes in three Lexington subdivisions. Curt Farley, director of Lexington's Division of Building Inspection, has asked state officials to re-examine the building code's requirements for attaching a residential roof.

Two structural engineers said builders can take inexpensive measures to significantly decrease damage along the edge of a tornado's path.

About $30, for example, can buy enough 50-cent metal fasteners to attach roof trusses to their load-bearing exterior walls. The "hurricane clips" make the connection more resistant to uplifting winds.

But some construction companies use nails driven at an angle, a "toe-nail" connection. The nails are fine under Kentucky's residential building code, but some experts say they're inadequate.

"That's an irresponsible way to build a house," said Jason Smart, a structural engineer with the Institute for Business and Home Safety, a Florida-based advocacy group backed by insurance companies. "Using toe-nail connections is not a valid option."

The nails provide little resistance against the upward sucking pressure of a tornado, he said. As nail after nail pops out, entire roofs become large sails that simply fly away.

The Kentucky Housing Corp. and Habitat for Humanity have required "hurricane clips" for several years on any home the organizations help finance or build.

"We wanted to raise the level of construction standards," said Tom Carew, director of design and construction review for the Kentucky Housing Corp., which provides subsidy financing for low-income housing. "It adds so little cost and can make the difference in certain situations."

The recent storms are changing the ways of some homebuilders.

Nick Gaines, who built houses in one of the hard-hit Lexington subdivisions, said he expects to be using "hurricane clips" soon.

"I'm sure every builder in Lexington will take some kind of measures to help sturdy up their houses," Gaines said.

Structural engineers also say homeowners should pay close attention to the types of exterior wall covering used on their houses. Plywood sheathing is recommended, but Kentucky's building code allows Styrofoam.