What started earlier this year as a simple patch job on the Theme Building at Los Angeles International Airport has turned into a long and costly struggle to rebuild one of L.A.’s most recognized landmarks.

After toiling for months on the peculiar structure, the airport is ready to reopen Encounter, the restaurant housed within, in the next few weeks. However, the scaffolding will likely remain in place through much of next year and possibly beyond as workers rebuild the structure’s exterior and upgrade the building to withstand earthquakes and high winds.

“The scope of the project has increased,” said Glenn Ito, the senior civil engineer for Los Angeles World Airports and who is in charge of the Theme Building project. “As we started looking at it more and more, we realized that it is much more involved than just re-stuccoing the building.”

Since a half-ton piece of stucco fell from the spider-like building’s upper arches in February, crews have worked to tear off and replace the old, asbestos-laden covering. But soon after work began on what was expected to be just a several-month project, workers unearthed a spate of problems in the structure that demanded attention: widespread rust in the underlying steel skeleton, a decaying concrete core, lead-based primer that needed removal and possible seismic deficiencies.

Los Angeles architecture firm Gin Wong Associates was awarded a $1.1 million contract last month by the Board of Airport Commissioners to draw up plans for a redesign of the building’s arches and central core. Those plans are expected in early November.

Ito said there is no estimate for the cost of the repairs, but planners hope to keep it under $10 million.

Shortly after the 1,000-pound slab of stucco fell, the airport was forced to close Encounter. The news was a blow to the airport, which has sustained image problems recently due to its aging facilities. What’s more, the airport has lost an estimated $140,000 in revenue from the restaurant in the six months it has been closed. The airport receives a percentage of the restaurant’s revenue.

The airport’s commissary, a cafeteria and offices underneath the structure have remained opened.

CSA Constructors Inc., a Paramount construction contractor, finished removing the building’s stucco paneling on Thursday. The company, which has done work on a number of airport projects previously, was awarded the emergency $1.8 million contract earlier this year after completing a $17 million renovation of the airport’s security checkpoints.

Bill Chisholm, CSA vice president, said his crew had to work fast to ensure that no additional pieces would fall off and endanger passersby.

“My objective is to make it safe,” he said. “It’s not a huge job but a job that could have huge implications.”

Now that the initial phase is complete, workers will soon begin the larger repair job, which includes fixing the steel in the upper arches, strengthening the central concrete core, seismically retrofitting the building and recladding the exterior of the structure.

Meanwhile, the airport is ready to give the restaurant clearance to restart operations, but it may still be a while before the doors officially open. Karen Tozer, concessions manager for the airport, said the restaurant’s managers may take some time to revamp the interior and hire new employees, which could delay its opening.

“Although it’s available by the beginning of October I don’t know that they’ll be able to open that soon,” she said. “But we’re very excited that we’re in a position now that we can have the restaurant reopen.”

To diffuse the impact of Encounter’s closure, some of the restaurant’s employees were moved to one of the other four airport restaurants operated by Buffalo, N.Y.-based Delaware North Cos. Inc., the concessions company that owns Encounter.

Kurt Clausen, general manager for Delaware North’s LAX operations, said the restaurant’s closure has likely cost his company millions of dollars, and even when it does reopen, the unappealing scaffolding and surrounding construction will likely keep revenues suppressed.

The retro-futuristic Theme Building has been a Los Angeles landmark since it opened in 1961. And since the structure has been designated a historic-cultural monument by the City Council, the airport is restricted from making significant alterations to the building’s appearance. In order to facilitate a more accurate recreation, Ito said workers took numerous photographs of the structure and used lasers to make a three-dimensional model of the structure before work began.

But the unique shape of the structure has made both the partial demolition and rebuilding planning difficult for engineers, Ito said.

“It’s been a real challenge for our structural engineers because of the unique shape of the building and the unique design of the building,” he said. “It’s certainly not a conventional design.”