EXHIBIT 21 BUILDING MATERIALS CORPORATION OF AMERICA LIST OF SUBSIDIARIES COMPANY STATE OF INCORPORATION ================================================================================ BMCA Insulation Products Inc. Delaware BMCA Quakertown Inc. Delaware Building Materials Investment Corporation Delaware Building Materials Manufacturing Corporation Delaware GAF Leatherback Corp. Delaware GAF Materials Corporation (Canada) Delaware GAF Premium Products Inc. Delaware Wind Gap Real Property Acquisition Corp. Delaware GAF Real Properties, Inc. Delaware GAFTECH Corporation Delaware LL Building Products Inc. Delaware Ductwork Manufacturing Corporation Delaware Pequannock Valley Claim Service Company, Inc. Delaware South Ponca Realty Corp. Delaware