The lowest bid for the Padanaram causeway rehabilitation project recently came in $2.2 million above the initial estimate and state officials want to know why.

On Monday, Department of Public Works Director David Hickox updated the Select Board on the project, which was expected to cost $6 million.

After the project went out to bid in the fall, 10 companies submitted cost estimates. The lowest bid was $8.2 million.

The Massachusetts Department of Transportation will fund a large portion of the work. The agency is now looking for ways to cut costs, Hickox said.

“As a result of being over budget Mass DOT has evaluated the project looking for reasons why it came in above the estimate,” Hickox said. “In addition to that, they are looking at other funding sources to close the $2.2 million gap.”

He said the state will put the project back out to bid later this year.

Preliminary designs call for rebuilding the road and replacing guard rails and sidewalks. The project is expected to take one year to complete once begun. During reconstruction the Padanaram Bridge will be closed.

Hickox said the town planned to undertake much-needed bridge repairs while the causeway is shut down to lessen the impact on drivers who use the route.

“We wanted to do that work when the causeway was out of commission so we wouldn’t inconvenience folks any more than we had to,” he said.

Repairs to the bridge’s center pier are required, Hickox noted.

There is currently $342,000 of federal money earmarked for the work, which was leftover from repairs made to the Little River Bridge 10 years ago. Additionally, voters at last year’s Annual Town Meeting approved spending $250,000 for bridge repairs.

“That’s the good news,” Hickox said. “The money is in place.”

However, there’s a possibility the federal government may allocate those funds to the causeway instead of the bridge repairs.

Hickox said the money was originally earmarked for bridge repairs and hopes that it’s spent for that purpose.

He told board members it’s unclear whether that will be the case.