EXHIBIT 21 NCI BUILDING SYSTEMS, INC. List of Subsidiaries <Table> NCI Holding Corp. Delaware NCI Operating Corp. Nevada Metal Coaters of California, Inc. Texas NCI Building Systems, L.P. Texas A&S Building Systems, L.P. Texas Metal Building Components, L.P. Texas NCI Group, L.P. Texas Building Systems de Mexico, S.A. de C.V. Mexico </Table>