Repair work is expected to begin soon on the most seriously damaged slate tiles on the Watkins Community Museum of History’s storm-damaged roof.

The replacement slate has been cut and prepared for delivery from a quarry in Glenville, N.Y., said Carmela Sibley, president of the Douglas County Historical Society’s board of directors, which oversees operations of the museum at 1047 Mass.

The roof was damaged by a hailstorm on April 23, 2006.

“We’re going to try to get as much of the roof in the original condition as absolutely possible,” Sibley said.

But under an agreement with the museum’s insurance company, the only slates to be replaced are the most seriously damaged or those that might fall, Sibley said. The museum and Allied Insurance still must come to terms on any additional roof replacement, she said.

“Another report will be submitted to the insurance company in terms of the rest of the roof for evaluation to see exactly what we have,” Sibley said.

The initial repair job will cost about $79,000 and will involve replacing no more than 100 tiles, said John Coffman, engineer with CMR Construction Co.’s Kansas City, Kan., office. The firm is headquartered in Dallas and is overseeing the project. The job probably will take two weeks, he said.

“I suspect once we get into it we will find that a whole lot more needs to be done,” Coffman said.

Coffman has prepared an inch-thick report on the roof, but he said the insurance company wants more information. His initial damage estimate was put at more than $1 million.

The museum’s roof is made of the same slate that was installed when the building was constructed 120 years ago. Few buildings have a roof that is 100 percent red slate, Coffman said.

The slate is so rare that only one quarry in the world produces it – the same one in Glenville that supplied the original slate, Coffman said.

Despite its age, the museum structure is in good shape, Coffman said. “It’s very well-built,” he said.

The roof damage didn’t cause any leaks or problems inside the building, museum director Rebecca Phipps said.

Coffman said he doesn’t think there are damaged tiles that could fall from the roof to the sidewalk.

“The building has been designed in such a way that they rarely will come off the building ,” he said. “They would get caught by the guttering.”