Southwark Metal Manufacturing Co., headquartered in Philadelphia, is building a 79,950-square-foot plant in Caldwell's Sky Ranch Business Center near the airport.

The company makes ductwork for new residential construction.

The $3.25 million plant will be the company's sixth location across the United States.

Up to 25 jobs will be created when the plant opens in October, owner Bill Spiegel says. There will be a range of positions and salaries with the majority of assembly jobs, but he declined to give specific wages. The plant could employ up to 60 people in 2013, depending on expansion of sales in the Northwest, he said.

The company chose the Treasure Valley for its central location in the Northwest. The plant will supply distributors in Utah, Idaho, Oregon, Washington, Wyoming, Nevada and Montana. At this time, the company's Nebraska plant serves distributors in Utah.

Southwark Metal Mfg. Co., family owned for three generations, has been manufacturing prefabricated sheet metal ducts and fittings for more than 60 years.

Spiegel would not share revenues but said the company is profitable and one of the biggest suppliers of residential ductwork.

K2 Construction Inc. of Boise is the general contractor. Up to 70 construction jobs were created by the project.