Exhibit 4.7  SECOND SUPPLEMENTAL
INDENTURE  SECOND
SUPPLEMENTAL INDENTURE, dated as of December 29, 2006 between BMCA Newco
Inc., a Delaware corporation (the New Guarantor), Building Materials
Corporation of America, a Delaware corporation (the Company), the
existing Guarantors signatory hereto (the Existing Guarantors) and
Wilmington Trust Company, as trustee under the Indenture referred to below (the
Trustee).  W I T N E S S E T H :  WHEREAS,
Indenture dated as of July 26, 2004 (as heretofore amended and
supplemented, the Indenture), was executed and delivered by the
Company, certain guarantors named therein and the Trustee, providing for the
issuance of the 7.75% Senior Notes Due 2014 and the Series B 7.75% Senior
Notes Due 2014 (collectively, the Securities) (capitalized terms used
herein but not otherwise defined have the meanings ascribed thereto in the
Indenture);  WHEREAS,
as a result of the guarantee by the New Guarantor of the Credit Agreement,
pursuant to Section 4.18 of the Indenture, the Company is required to
cause the New Guarantor to execute and deliver to the Trustee this Second
Supplemental Indenture pursuant to which the New Guarantor shall provide a
Guarantee as set forth in Article X of the Indenture;  WHEREAS,
Section 9.01(5) of the Indenture provides that the Company, the
Guarantors and the Trustee may amend the Indenture and the Securities without
notice to or consent of any Holders of the Securities to add Subsidiary
Guarantees; and  WHEREAS,
this Second Supplemental Indenture has been duly authorized by all necessary
corporate action on the part of the New Guarantor.  NOW,
THEREFORE, in consideration of the premises set forth above and for other good
and valuable consideration, the receipt of which is hereby acknowledged, the
Company, the Existing Guarantors, the New Guarantor and the Trustee mutually
covenant and agree for the equal and ratable benefit of the Holders as follows:  ARTICLE I  Agreement to Guarantee  Section 1.1.  Agreement to Guarantee.  Subject to Section 10.07 of the
Indenture, the New Guarantor hereby agrees, jointly and severally with all
other Guarantors, irrevocably and unconditionally, to guarantee the punctual
payment when due, whether at maturity, by acceleration, by redemption or
otherwise, of all monetary obligations of the Company under the Indenture and
the Securities, on the terms and subject to the conditions set forth in Article X
of the Indenture, which guarantee shall be


subject
to automatic release in accordance with the provisions of Section 10.09 of
the Indenture.  Section 1.2.  Trustees Acceptance.  The Trustee hereby accepts this Second
Supplemental Indenture and agrees to perform the same under terms and
conditions set forth in the Indenture.  ARTICLE II  Miscellaneous  Section 2.1.
 Effect of Second Supplemental
Indenture.  Upon the execution and
delivery of this Second Supplemental Indenture by the Company, the Existing
Guarantors, the New Guarantor and the Trustee, the Indenture shall be
supplemented in accordance herewith, and this Second Supplemental Indenture
shall form a part of the Indenture for all purposes, and every Holder of
Securities heretofore or hereafter authenticated and delivered under the
Indenture shall be bound thereby.  Section 2.2.  Indenture Remains in Full Force and Effect.  Except as supplemented hereby, all provisions
in the Indenture shall remain in full force and effect.  Section 2.3.  Indenture and Second Supplemental
Indenture Construed Together.  This
Second Supplemental Indenture is an indenture supplemental to in and
implementation of the Indenture, and the Indenture and this Second Supplemental
Indenture shall henceforth be read and construed together.  Section 2.4.  Confirmation and Preservation of Indenture.  The Indenture as supplemented by this Second
Supplemental Indenture is in all respects confirmed and preserved.  Section 2.5.  Conflict with Trust Indenture Act.  If any provision of this Second Supplemental
Indenture limits, qualifies or conflicts with any provision of the TIA that is
required under the TIA to be part of and govern any provision of this Second
Supplemental Indenture, the provision of the TIA shall control.  If any provision of this Second Supplemental
Indenture modifies or excludes any provision of the TIA that may be so modified
or excluded, the provision of the TIA shall be deemed to apply to the Indenture
as so modified or to be excluded by this Second Supplemental Indenture, as the
case may be.  Section 2.6.  Severability.  In case any provision in this Second
Supplemental Indenture shall be invalid, illegal or unenforceable, the
validity, legality and enforceability of the remaining provisions shall not in
any way be affected or impaired thereby.  Section 2.7.  Benefits of Second Supplemental Indenture.  Nothing in this Second Supplemental Indenture
or the Securities, express or implied, shall give to any  2


Person,
other than the parties hereto and thereto and their successors hereunder and
thereunder and the Holders of the Securities, any benefit of any legal or
equitable right, remedy or claim under the Indenture, this Second Supplemental
Indenture or the Securities.  Section 2.8.  Successors.  All agreements of the New Guarantor in this
Second Supplemental Indenture shall bind its successors except as provided in
the Indenture.  All agreements of the
Trustee in this Second Supplemental Indenture shall bind its successors.  Section 2.9.  Certain Duties and Responsibilities of the
Trustee.  In entering into this
Second Supplemental Indenture, the Trustee shall be entitled to the benefit of
every provision of the Indenture and the Securities relating to the conduct or
affecting the liability or affording protection to the Trustee, whether or not
elsewhere herein so provided.  Section 2.10.  Governing Law.  This Second Supplemental Indenture shall be
governed by, and construed in accordance with, the laws of the State of New
York. The Trustee, the Company, the Guarantors and the Securityholders agree to
submit to the jurisdiction of the courts of the State of New York in any action
or proceeding arising out of or relating to the Indenture, this Second
Supplemental Indenture or the Securities.  Section 2.11.  Multiple Originals.  The parties may sign any number of copies of
this Second Supplemental Indenture.  Each
signed copy shall be an original, but all of them together represent the same
agreement.  One signed copy is enough to
prove this Second Supplemental Indenture.  Section 2.12.  Headings.  The Article and Section headings herein
have been inserted for convenience of reference only, are not intended to be
considered a part hereof and shall not modify or restrict any of the terms or
provisions hereof.  3


IN
WITNESS WHEREOF, the parties hereto have caused this Second Supplemental
Indenture to be duly executed as of the date first written above.  New GuarantorBMCA
  Newco Inc.By:
  /s/ John MaitnerName:
  John
  MaitnerTitle:
  Vice
  President, TreasurerCompanyBUILDING
  MATERIALSCORPORATION
  OF AMERICABy:
  /s/ John MaitnerName:
  John
  MaitnerTitle:
  Vice
  President, Treasurer


Existing GuarantorsBUILDING MATERIALS
  INVESTMENT CORPORATIONBMCA INSULATION PRODUCTS
  INC.BUILDING MATERIALS
  MANUFACTURING
  CORPORATIONDUCTWORK MANUFACTURING
  CORPORATIONGAF MATERIALS CORPORATION
  (CANADA)GAF PREMIUM PRODUCTS INC.GAF REAL PROPERTIES, INC.GAFTECH CORPORATIONLL BUILDING PRODUCTS INC.PEQUANNOCK VALLEY CLAIM
  SERVICE COMPANY, INC.SOUTH PONCA REALTY CORP.BMCA QUAKERTOWN INC.WIND GAP REAL PROPERTY
  ACQUISITION CORP.HBP ACQUISITION LLCBy:
  /s/ John MaitnerName:   John MaitnerTitle:     Vice
  President, Treasurer


TrusteeWILMINGTON
  TRUST COMPANYBy:
  /s/ Kristin L. MooreName:   Kristin
  L. MooreTitle:     Authorized
  Signatory