The old coating is being removed, Superintendent Robert Dexter explained on the roof Wednesday afternoon. It's like a plastic bag. It keeps moisture from getting through, but that traps moisture in the stone.
"It was well-intended," he said. "But if moisture gets in there, things start to deteriorate."
The new coating, Dexter says, is a membrane that allows the rock to exhale moisture, but keeps rain from being absorbed.
It might be likened to the window of a police interrogation room that reflects like a mirror into the room, but allows a view into the room.
Now, painters are applying a substance to adhere to the old sealant. On top of that is a plastic sheet that's used to strip off the old coating, Dexter explained.
Meanwhile, wood frames were being built this week for molds to make new sections of the short wall around the roof, the superintendent said.
"These lower walls just received a wood blocking," Dexter said near that part of the restoration project as he held back a white rubberized roofing material that's to be replaced. It was pulled away to install new blocking boards for a metal wrapping, and it's been placed back over the low wall until it's removed again to accommodate new metal.
"All of this will be covered with a metal cap," he said.
The architect and county commissioners decided to accept a recommendation by a roofing subcontractor for D.F. Chase Construction, the Nashville-based general contractor who employs Dexter.
Using aluminum is better than using copper again, he said. Copper, however, will be used at the clock towers.
Thursday, Dexter anticipated the Florida-based clock repairman to arrive and take the clockworks back to his shop.
County commissioners appropriated more than $400,000 to replace the roof and restore other fixtures, walls, clocks and towers atop the building.
Among the sub-contractors' crews is Ricky Begley of the Marshall County part of Rally Hill, a painter with Franklin-based Charlie Irwin Painting Co.
"We're all thankful," Begley said, "because a lot of people are out of work and Charlie is one of the subcontractors who has work.
"I also pay taxes in Marshall County," Begley said.