BAYPORT — Andersen Corp. plans to expand its window and door manufacturing operations in Cottage Grove and North Branch.

The company is expected to announce the expansion today. Three-hundred jobs will be created. Andersen is headquartered in Bayport and is said to be the largest window and patio door maker in the U.S. The $45 million manufacturing expansion follows a recently completed addition in Bayport.

CEO Jay Lund said the company has benefited from the recovering housing market. Lund attributes some of Andersen’s recent growth to a rise in demand for multifamily housing and an improved market for home improvements.