One of Washington's largest window makers, Milgard Manufacturing Inc., will close its Marysville plant and lay off 80 employees due to falling demand from the housing market. The 80 manufacturing employees will be laid off starting soon, although about 10 sales and service people will remain. Speaking from Milgard headquarters in Tacoma, the Director of Employee Relations said she hopes the Marysville closure will reduce head count enough to prevent layoffs in Tacoma. About 820 people make Milgard windows there, supported by about 100 in administration. Milgard is owned by Masco Corp. of Taylor, Mich., which purchased Milgard in 2001.