In the spring, water gushed through the ceiling at Charleston International Airport, flooding the United Airlines ticket office.

In January, construction workers uncovered asbestos as they ripped apart airport walls.

Over the past several months, changes to materials inside the new rental car pavilion and elsewhere have dipped into an $11.2 million contingency fund set up as part of the nearly $200 million overhaul of the aging airport terminal.

Scuff marks on the newly installed terrazzo flooring immediately after it was installed in the first section of the airport to be completed sent shivers through airport officials, since the material is set to be installed throughout the terminal to eliminate the clickety-clack of luggage rolling over the uneven tile that's been in place for 30 years.

Setbacks and unexpected expenses are all part of any major construction project, but so far work has been delayed just one month, now set for completion in September 2015, unless another problem pops up.

With about 15 months to go, Matt McCoy, program manager with the Michael Baker Inc. firm hired to oversee the massive makeover, recently said work is about 30 or so percent completed.

Airport passengers, for the most part, don't see the expansion and renovation affecting them.

Marcie DiAleo of Boston didn't notice all the construction going on when she visited the area recently.

Judith Crowell of Miami said airport officials have managed to keep it isolated. "It's clean and it's not interfering with anything," she said.

Kathy Bergman of Minnesota drove into the airport parking garage and said everything was well-marked and easy to get to.

Lee Hammett of Idaho said, "You may be doing construction, but it didn't appear to be making life harder getting in and getting out of the airport."

They are among the nearly 3 million tourists and business people flying in and out of the state's busiest airport as it undergoes the overdue face-lift.

Construction is on schedule with minimal complaints, said Paul Campbell, director of the airport and its two smaller counterparts in Mount Pleasant and on Johns Island, all operated by Charleston County Aviation Authority.

Behind the scenes

On a recent walk-through of the terminal, including its underbelly, the little-used international station and the framework for what will be a 30 percent increase in the size of the terminal, Campbell and Deputy Director of Facilities John Connell pointed out some interesting features. They include nearly 2,000 new feet of baggage belts beneath the facility and arched pieces of steel lying in front of the terminal slated for the dome to be installed over the atrium.

They also pinpointed the area between the ticket counters of Southwest Airlines and US Airways as the site of the new entranceway to the eight-lane consolidated security checkpoint that boarding passengers must go through before continuing to their gates.

The boardroom will move from overlooking the backside of the atrium to hugging its right side. Concessionaires will sit below the board room. Administrative offices will sit above the security lanes.

Five new gates are being added on Concourse B, and new jet bridges will ferry passengers on and off planes at all 15 gates. The airport now has 10 gates.

A third baggage carousel has been added, but it's closed off for now as workers begin to raise the ceiling throughout the current 330,000-square-foot terminal. Fifteen new boarding bridges will be housed near the airport police station until they are ready to be installed. New chillers and other equipment will be set up in the new central energy plant, built away from the terminal in a stand-alone building.

Exposed wiring and pipes hover behind temporary walls erected to shield the airport's passengers from the untidiness of construction work and its possible hazards.

"We have wiring running all over the place," Campbell said. "You have to trace it down and find where it goes."

Delta's ticket counter is being moved across the lobby from the others to make way for demolition and renovation of each airline's check-in station. In front of the new glass wall that will span the terminal's front façade, concrete benches with recessed lighting underneath will be erected.

"We are increasing the passenger load and adding more flights at the same time we are deconstructing and constructing the terminal," Campbell said. "By this time next year, we will be close to having a functioning airport with 15 gates. There will still be aesthetics to be finished after September 2015. When it's done though, it's going to be fantastic."

Reach Warren L. Wise at 937-5524 or twitter.com/warrenlancewise.