Legend Valve & Fitting Inc. is adding 55,000 square feet to its 153,000-square-foot Auburn Hills, Michigan facility, according to a story in Crain’s Detroit Business.

Company officials say the $4 million expansion is the result of rising demand for its products in commercial and residential markets.

Construction started in June and is expected to be completed in November. The addition will mainly be for extra warehousing space, but the expansion also includes adding more manufacturing equipment, including a new extruder, in the company’s existing space.

David Hickman, president and CEO of the company, told the newspaper Legend has recently hired a dozen new employees and plans to hire more.