When the Missoula County Detention Center opened 20 years ago, the roof was expected to last a full 30 years. But that's not going to happen, a county official said Tuesday.

With the roof past its prime, commissioners approved a $610,000 contract with Shrock Commercial Roofing of Missoula to install a new PVC membrane with a true 30-year warranty.

Larr Farnes, head of Facilities Management, said Shrock submitted the lowest bid and can start work as early as June. The second lowest bid couldn't get to work until late summer, he added.

“We've gone through four different companies over five different years getting plans and quotes and finding out what needs to be done,” said Farnes. “This is a project we've needed for about five years. We've been putting patches on to the tune of about $25,000 to $30,000 a year. It's beyond patching now, so it's just time to replace the roof.”

Last October, the county announced its plans to install rooftop solar at the detention center as part of a wider push toward renewable energy. While that project is still on track, Farms said, the effort will likely shift to a ground-mounted array, not rooftop solar.

A meeting Monday placed the preferred location on the north side of the detention center. At that location, Farnes said, more kilowatt hours could be achieved.

“With roof mounted, there's some structural issues,” Farnes said. “The slope of the roof and type of roof it is makes it hard to get enough support to support the solar panels. Putting solar panels on the roof would cost a lot more money.”

The Missoula County Detention Facility opened in November 1999 and replaced the outdated and often crowded facility on the top floor of the downtown courthouse annex.

The facility's roof was expected to last 30 years, though Farnes said it began wearing out years ago, requiring repeated patches and fixes. He said the new material will include a true 30-year warranty.

“What we found was the material they were using 20 years ago didn't last the 30-year period they thought,” he said. “This PVC material – the longevity is better than the roof we had before. As time goes on, they find better materials.”

Andrew Czorney, the county's chief financial officer, said the project would be covered by special funds set aside in various accounts, including the capital reserve account and the commissary account at the detention center.