The cost of a Silver Spring transit hub that has been delayed repeatedly has ballooned by about $11 million, county officials said Monday.

Now at $112 million, the price tag for the Silver Spring Transit Center is more than three times the original $35 million estimate. Montgomery County officials also said Monday that the project, which is several years behind schedule, could be completed by August at the earliest.

Since its inception, the transit center — which would serve 100,000 people a day and bring together buses, Metro rail and MARC trains in the heart of Silver Spring’s revitalized downtown — has been beset by problems. In the past decade, its opening has been delayed at least seven times by changes in construction plans and insufficient funding.

The most recent snag came in January, when the county alleged that construction workers improperly poured concrete on two floors of the building. Foulger-Pratt, the contractor in charge of construction, quickly fired back, saying the building was structurally sound.

It remains unclear whether concrete replacement or other solutions are needed. Foulger-Pratt recently submitted data to the county that it says show the concrete work is solid.

David Dise, the county’s general-services director, said his staff is analyzing the data and will start negotiations with Foulger-Pratt in May. If the county decides that the concrete is fine as is, then the construction should be completed by Aug. 22, Dise said.

In an interview Monday, County Executive Isiah Leggett (D) said that if the county and Foulger-Pratt cannot come to an agreement, the county will sue.

Bryant F. Foulger, a principal at the company, did not respond to a request for comment Monday.

County officials said Foulger-Pratt would pay for fixing the concrete.

But the county must cover other costs caused by delays, such as additional inspections and changes in construction plans. Those have caused the project’s price tag to increase by $3.2 million, according to county documents that were part of a budget memo Leggett sent to the County Council last week. The cost was further increased by $7.4 million because of unexpected changes to construction and utility work, according to the documents.

Local tax revenue and government bonds would pay for about half of the increase, according to the documents. The federal government, the state of Maryland and the Washington Suburban Sanitary Commission would cover most of the additional costs.