Lilac Terrace, a 50-unit, four-story retirement housing project under construction on Spokane's North Side, is expected to be completed in October. Kop Construction Co., of Spokane, is the contractor on the $9.5 million project at the Lilac Plaza Retirement Community complex, at 7007 N. Wiscomb, and Zeck Butler Architects PS, of Spokane, designed it.