COLUMBIA — Something's not exactly on the level in the South Carolina Senate office building — the floor.

The six-story Marion Gressette Building, home to 46 state senators, their staffs and committees, is suffering some noticeable structural problems. Walls are bowing, concrete is cracking and parts of some upper floors have a noticeable three-inch slope.

Engineers are investigating, and hope to know the cause of these problems by the end of the year. But state officials already know one thing for sure: Repairing the building will be expensive, perhaps even cost millions.

And that is not a comforting thought in the middle of a state budget crisis.

"It couldn't come at a worse time," said Senate President Pro Tem Glenn McConnell. "I'm very concerned about this. We've been told it's not unsafe for what we're using the building for now. If we get word that it's not safe, we'll get our people out of there immediately."

The Senate staff was briefed on the building's condition this week, but so far there are no plans to evacuate. Apparently the 1970s-era building is OK for the moment, but McConnell said it's clear that things are getting worse. Caulking used to seal cracks in some of the buildings windows is now "stretched like bubble gum."

For now, the Senate has ordered staffs not to add any bookcases, file cabinets or any other equipment that might stress the floors.

Jeff Gossett, the clerk of the Senate, said engineers are doing a structural analysis of the building right now. He said it's not a question of whether there is a problem, it's how bad it is.

"There are some cracks in the concrete and the columns that give (the engineers) some concern," Gossett said. "We're trying to find out how deep that concern is."

Most of the floor slope occurs in the cantilevered parts of the building — an 11-foot overhang on the building that starts on the second floor. Floors are anchored to the building's center columns instead of relying on support of the floors beneath them. McConnell said the problem is that the concrete that has

been tested so far is far weaker than it should be.

He said the concrete is supposed to be rated to hold 4,000 pounds per square inch, but in many places the concrete floors test at between 1,000 and 3,000 psi.

Costs for shoring up the building are not set yet because a lot will depend on what the engineers find. McConnell said some contractors have given him an estimate of $300,000 to $500,000 to patch up the building; a full renovation to correct the problems could cost millions.

For now, the Senate plans to limit public access to the building when the General Assembly convenes in January. Senate committees may meet in the House office building, next door to the Gressette Building on the Statehouse campus.