THIRD SUPPLEMENTAL INDENTURE

THIRD SUPPLEMENTAL INDENTURE

THIRD SUPPLEMENTAL INDENTURE, dated as of October 31, 2006, among Ply Gem Industries, Inc. (the “Company”), Alcoa Home Exteriors, Inc. (“Alcoa”), and U.S. Bank National Association, as trustee (the “Trustee”).

WHEREAS, the Company, Ply Gem Holdings, Inc., Great Lakes Window, Inc., Kroy Building Products, Inc., Napco, Inc., Napco Window Systems, Inc., Thermal-Gard, Inc., Variform, Inc., and the Trustee entered into an indenture dated as of February 12, 2004 to provide for the issuance of the Company’s 9% Senior Subordinated Notes due 2012;

WHEREAS, the Company, MWM Holding, Inc. (“MWM Holding”), MW Manufacturers Corp. (“MW Manufacturers”), MW Manufacturers, Inc. (“MW”), Patriot Manufacturing, Inc. (“Patriot”), Lineal Technologies, Inc. (“Lineal”), and the Trustee entered into the First Supplemental Indenture, dated as of August 27, 2004, to provide for the addition of MWM Holding, MW Manufacturers, MW, Patriot and Lineal as Guarantors under the indenture dated as of February 12, 2004;

WHEREAS, the Company, AWC Holding Company (“AWC”), Alenco Holding Corporation (“Alenco”), Alenco Extrusion Management, L.L.C. (“AEM”), New Alenco Extrusion, Ltd. (“NAE”), Alenco Extrusion GA, L.L.C. (“AEGA”), Aluminum Scrap Recycle, L.L.C. (“ASR”), Alenco Building Products Management, L.L.C. (“ABP”), New Alenco Window, Ltd. (“NAW”), Alenco Window GA, L.L.C. (“AWGA”), Alenco Trans, Inc. (“AT”), Glazing Industries Management, L.L.C. (“GIM”), New Glazing Industries, Ltd. (“NGI”), Alenco Interests, L.L.C. (“AI”), and AWC Arizona, Inc. (“AWCA”), and the Trustee entered into the Second Supplemental Indenture, dated as of February 24, 2006, to provide for the addition of AWC, Alenco, AEM, NAE, AEGA, ASR, ABP, NAW, AWGA, AT, GIM, NGI, AI and AWCA as Guarantors under the indenture dated as of February 12, 2004 (as so supplemented, the “Indenture”);

WHEREAS, on the date hereof, the Company has acquired all of the issued and outstanding stock of Alcoa;

WHEREAS, pursuant to Section 4.16 of the Indenture, Alcoa, as a new Restricted Subsidiary, is required to enter into this Supplemental Indenture (the “Supplemental Indenture”) as a Guarantor;

WHEREAS, the Company, Alcoa and the Trustee are authorized to enter into this Supplemental Indenture;

NOW, THEREFORE, for and in consideration of the premises and the mutual covenants contained in this Supplemental Indenture and for other good and valuable consideration, the receipt and sufficiency of which are herein acknowledged, the Company, Alcoa and the Trustee hereby agree for the equal and the ratable benefit of all Holders of the Notes as follows:

DEFINITIONS