NASHVILLE (AP) — Renovations at the state Capitol are giving workers the chance to restore some of the original features of the 150-year-old building including arched ceilings and other detail work.

Peter Heimbach Jr. of the state Department of General Services told reporters during a tour Monday that while mechanical upgrades are the main object of the overhaul, the state will also have a chance to restore vaulted ceilings and to seal doors that weren't original to the building.

"We'd like to preserve some of the history of the Capitol and its construction," he said.

Tearing out drop ceilings on the ground level and in legislative staff offices revealed arched ceilings original to the building. Demolition work on the men's' bathroom on the first floor revealed the outline of a former staircase and faux detail work that had been painted on the wall.

The discoveries in the old stairwell will be covered up again as the bathroom will need to be replaced, but the exposed arches on the ground floor will remain open, including in a former vending and break area that will become a conference room.

"This type of construction really hasn't changed much since the Romans did it," Heimbach said. "There' s a lot of cathedrals in Europe that have this exact type of construction."

In a legislative office off the House floor, workers plan to replace a connecting door that wasn't part of the original building plans.

Workers also uncovered gas light fixtures that predate electricity and the hooks where electric lines were hung when the building was first wired.

"As safety improved and codes improved, that was obviously changed to putting things in conduit," Heimbach said.

Technological improvements have made it easier to rewire the building — up to a point.

"Except for the electrical services themselves, things have gotten smaller," he said. "For example, it takes much less to run a communications cable than it did 15 to 20 years ago, but there's a lot more of them."

One feature that won't be making a comeback is fireplaces, which were used before modern heating and cooling systems were invented.

The $15 million project has caused the governor, executive staff, constitutional officers and legislative workers to clear out of the building until December.

Heimbach noted that workers today have the advantage of an empty house when making the renovations. When ductwork was first installed in the 1950s, the building remained occupied.

Project architect Jim Thompson of Centric Architecture in Nashville said the demolition work has done nothing to lend credibility to the legend of an escape tunnel from the governor's office to the Cumberland River.

"The story of the governor's escape tunnel is totally an urban myth," he said.

While the floor between the governor's office and the ground floor has a covered hole in it, that feature is not unique, Thompson said.

"These round holes are throughout the building," he said. "We don't know what they were to start with."