Concrete needed to repair cracks in the troubled Silver Spring Transit Center cannot be applied until spring. (Sarah L. Voisin/The Washington Post)

A new two-inch layer of concrete needed to repair cracks on the second and third levels of the troubled Silver Spring Transit Center cannot be applied until spring, Montgomery General Services director David Dise reported Tuesday.

Dise had previously expressed hopes that workers could beat the onset of cold temperatures to pour the latex-modified concrete. But recent weather has driven temperatures below the 40-degree threshold recommended for new concrete. It means that repairs on the $120 million bus-and-train hub, originally scheduled to open in 2011, will not be complete until mid-2014 at the earliest.

Officials have not committed to a new opening date.

“Beating the ‘weather window’ has been a concern throughout the remediation schedule. It now appears that this window is closed,” Dise said in a letter to County Executive Isiah Leggett (D) and County Council President Nancy Navarro (D-Midcounty). “Contractors experienced with [latex modified concrete] application strongly advise that we proceed with this work when prevailing air and surface temperatures are consistently above 40ºF, which will likely be in late March or early April.”

Dise’s letter did not specify why workers had not been able to make the “weather window.” In recent briefings for the County Council he said that pouring the new concrete in a timely manner was contingent on approval from Metro and the county’s Department of Permitting Services. The department also needed to approve plans for “roughing” the existing concrete surface, creating irregularities to help create a bond with the new latex covering. When the pouring of the new surface begins, it is expected to take about six weeks.

A March report by KCE, an engineering firm hired by the county, found that the center was unusable and unsafe without major repairs. Since summer, the county, general contractor Foulger-Pratt and designer Parsons-Brinckerhoff have been collaborating on remediation.

Dise told Leggett and Navarro that fixes to two key segments of roadway on the second level—involving concrete for 18 new supporting beams—are complete. With the exception of the concrete overlay, he said, all other repairs would be completed over the winter. That includes possible further work on interior beams and girders to reinforce them against shear and torsion forces. Dise said later this month Parsons will meet with the county and KCE staff to review its original calculations.