Exhibit 4.1


    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:

     

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

     

    ARTICLE
      I
  

     

    DEFINITIONS

     

    1.1  Definitions.
      For
      purposes of this Supplemental Indenture, the terms defined in the recitals
      shall
      have the meanings therein specified; any terms defined in the Indenture and
      not
      defined herein shall have the same meanings herein as therein defined; and
      references to Articles or Sections shall, unless the context indicates
      otherwise, be references to Articles or Sections of the Indenture.

     

     

     

    ARTICLE
      II   

     

    GUARANTEES
      OF NOTES AND OTHER PROVISIONS

     

    2.1  Guarantees.

     

    (a)  Alcoa
      hereby, jointly and severally with the other Guarantors, unconditionally and
      irrevocably guarantees to each Holder of a Note authenticated and delivered
      by
      the Trustee and to the Trustee and its successors and assigns, irrespective
      of
      the validity and enforceability of the Indenture, the Notes or the obligations
      of the Issuers or any other Guarantors to the Holders or the Trustee hereunder
      or thereunder: (a) (x) the due and punctual payment of the principal
      of, premium, if any, and interest on the Notes when and as the same shall become
      due and payable, whether at maturity, upon redemption or repurchase, by
      acceleration or otherwise, (y) the due and punctual payment of interest on
      the overdue principal and (to the extent permitted by law) interest, if any,
      on
      the Notes and (z) the due and punctual payment and performance of all other
      obligations of the Issuer and all other obligations of the other Guarantors
      (including under the Note Guarantees), in each case, to the Holders or the
      Trustee hereunder or thereunder (including amounts due the Trustee under
      Section 7.07 of the Indenture), all in accordance with the terms hereof and
      thereof (collectively, the “Guarantee Obligations”); and (b) in case of any
      extension of time of payment or renewal of any Notes or any of such other
      obligations, the due and punctual payment and performance of Guarantee
      Obligations in accordance with the terms of the extension or renewal, whether
      at
      maturity, upon redemption or repurchase, by acceleration or otherwise. Failing
      payment when due of any amount so guaranteed, or failing performance of any
      other obligation of the Issuers to the Holders under the Indenture or under
      the
      Notes, for whatever reason, Alcoa shall be obligated to pay, or to perform
      or
      cause the performance of, the same immediately. A Default under the Indenture
      or
      the Notes shall constitute an event of default under the Note Guarantees, and
      shall entitle the Holders of Notes to accelerate the obligations of Alcoa
      thereunder in the same manner and to the same extent as the obligations of
      the
      Issuers.

     

    (b)  Alcoa,
      the Trustee and each Holder by its acceptance of a Note hereby agrees that
      the
      Note Guarantee of Alcoa provided hereunder shall be subject to all terms,
      provisions and conditions in the Indenture that relate to a Note Guarantee
      (including, without limitation, Article 11 of the Indenture). Alcoa further
      agrees to be bound by, and to comply with, all provisions of the Indenture
      and
      Note Guarantee that are applicable to a Guarantor that is a Restricted
      Subsidiary.

     

    2.2  Execution
      and Delivery of Note Guarantees.
      The
      delivery of any Note by the Trustee, after the authentication thereof under
      the
      Indenture, shall constitute due delivery of the Note Guarantees on behalf of
      Alcoa.

     

    2.3  No
      Personal Liability.
      No
      stockholder, officer, director, employee or incorporator, past, present or
      future, of Alcoa, as such, shall have any personal liability under the Note
      Guarantees of Alcoa by reason of his, her or its status as such stockholder,
      officer, director, employee or incorporator.

     

     

     

    ARTICLE
      III   

     

    MISCELLANEOUS

     

    3.1  Effect
      of the Supplemental Indenture.
      This
      Supplemental Indenture supplements the Indenture and shall be a part and subject
      to all the terms thereof. Except as supplemented hereby, the Indenture and
      the
      Notes issued thereunder shall continue in full force and effect.

     

    3.2  Counterparts.
      This
      Supplemental Indenture may be executed in counterparts, each of which shall
      be
      deemed an original, but all of which shall together constitute one and the
      same
      instrument.

     

    3.3  GOVERNING
      LAW.
      THIS
      SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH,
      THE LAWS OF THE STATE OF NEW YORK.

     


    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    


    


     

    IN
      WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture
      to
      be duly executed on this 31st day of October, 2006.

     

     

    PLY
      GEM
      INDUSTRIES, INC.

     

     

    By:___________________________

     

                                  Name:
      Shawn K.
      Poe

                              Title:
      Vice President, and Chief
      Financial 

                      Officer,
      Treasurer and Secretary 

     

     

     

    ALCOA
      HOME EXTERIORS, INC.

     

     

    By:___________________________ 

         

    Name:
      Shawn
      K.
      Poe

                        Title:
      Vice President, Treasurer and Secretary

     

     


    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    


    


     

    U.S.
      BANK
      NATIONAL ASSOCIATION,

    as
      Trustee

     

    By:_______________________

     

    Name:
      

                                    Title: