FOURTH
SUPPLEMENTAL INDENTURE




FOURTH
SUPPLEMENTAL INDENTURE, dated as of May 29, 2008, among Ply Gem Industries, Inc.
(the “Company”), Ply Gem Pacific Windows Corporation (“Pacific Windows”) 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;




WHEREAS,
the Company, Alcoa Home Exteriors, Inc. (“Alcoa”), and the Trustee entered into
the Third Supplemental Indenture, dated as of October 31, 2006, to provide for
the addition of Alcoa as a Guarantor under the indenture dated as of February
12, 2004 (as so supplemented, the “Indenture”);




WHEREAS,
the Company has acquired all of the issued and outstanding stock of Pacific
Windows;




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




WHEREAS,
the Company, Pacific Windows 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, Pacific Windows 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)  Pacific
Windows 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, Pacific Windows 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 Pacific Windows thereunder in
the same manner and to the same extent as the obligations of the
Issuers.




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(b)  Pacific
Windows, the Trustee and each Holder by its acceptance of a Note hereby agrees
that the Note Guarantee of Pacific Windows 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).  Pacific Windows 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 Pacific Windows.




2.3  No Personal
Liability.  No stockholder, officer, director, employee or
incorporator, past, present or future, of Pacific Windows, as such, shall have
any personal liability under the Note Guarantees of Pacific Windows 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.




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IN
WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to
be duly executed on this ____ day of May, 2008.






PLY
      GEM INDUSTRIES, INC.






By:
            ___________________________






Name:  Shawn
      K. Poe


Title:    Vice
      President, Chief Financial
              Officer, Treasurer and Secretary






PLY
      GEM PACIFIC WINDOWS CORPORATION




By:
            ___________________________


Name:  Shawn
      K. Poe


Title:    Vice
President, Treasurer and Secretary







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U.S.
      BANK NATIONAL ASSOCIATION,




as
      Trustee




By:




Name:




Title:




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