DEXTER — When Continental Construction Co., Gouverneur, announced a 110-day work schedule for the renovation of Watertown International Airport in June, Spike C. Decker started doing some quick math in his head.

"I said: 'Shoot, that's not going to hit our Sept. 16 timeline for when Cape Air is coming,'" the Jefferson County buildings and grounds superintendent said. Mr. Decker then asked the general contractor: "'Can you get it done a little quicker?' They said: 'Spike, it's already an aggressive schedule.'"

Enter plan B.

The county will turn its 9,600-square-foot south hangar into a temporary terminal until contractors finish the $621,711 renovation next door. The hangar was the maintenance facility for the now-defunct Big Sky Airlines, and was renovated in the winter of 2007.

Mr. Decker said the temporary digs were approved by both Cape Air, Hyannis, Mass., and the Transportation Security Administration.

"They all agree that when it comes to the public, we shouldn't have them stepping over extension cords," he said.

Mr. Decker said some windows, doors and lighting fixtures also won't be installed before the return of air service. If suppliers make their delivery dates, the superintendent said, the project will be completed by Oct. 11.

County crews will start building the temporary site Tuesday, borrowing wood from the county Highway Department and furniture from the old terminal.

"We're going to get out of this very, very inexpensively," said Mr. Decker, adding he had planned for this contingency when work started June 23. He estimated the cost to build the temporary space at $1,000.

At the main site, Continental is being assisted by Hyde-Stone Mechanical Contractors Inc., Watertown, for mechanical and plumbing work, and Blackstone Electric, Watertown, for electrical work. Mr. Decker said the project is still at or under budget.