Exhibit 4.8  THIRD SUPPLEMENTAL INDENTURE  THIRD
SUPPLEMENTAL INDENTURE, dated as of December 29, 2006 between BMCA
Acquisition Inc. and BMCA Acquisition Sub Inc., each a Delaware corporation,
and BMCA Gainesville LLC, a Delaware limited liability company (collectively,
the New Guarantors), 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 Guarantors of the Credit Agreement,
pursuant to Section 4.18 of the Indenture, the Company is required to
cause the New Guarantors to execute and deliver to the Trustee this Third
Supplemental Indenture pursuant to which the New Guarantors 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 Third Supplemental Indenture has been duly authorized by all necessary
corporate action on the part of the New Guarantors.  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 Guarantors 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, each 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 Third
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 Third Supplemental Indenture.  Upon the execution and delivery of this Third
Supplemental Indenture by the Company, the Existing Guarantors, the New
Guarantors and the Trustee, the Indenture shall be supplemented in accordance
herewith, and this Third 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 Third Supplemental Indenture
Construed Together.  This Third
Supplemental Indenture is an indenture supplemental to in and implementation of
the Indenture, and the Indenture and this Third Supplemental Indenture shall
henceforth be read and construed together.  Section 2.4.  Confirmation and Preservation of Indenture.  The Indenture as supplemented by this Third
Supplemental Indenture is in all respects confirmed and preserved.  Section 2.5.  Conflict with Trust Indenture Act.  If any provision of this Third 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 Third
Supplemental Indenture, the provision of the TIA shall control.  If any provision of this Third 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 Third Supplemental Indenture, as the
case may be.  Section 2.6.  Severability.  In case any provision in this Third
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.  2


Section 2.7.  Benefits of Third Supplemental Indenture.  Nothing in this Third Supplemental Indenture
or the Securities, express or implied, shall give to any 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 Third Supplemental Indenture or the
Securities.  Section 2.8.  Successors.  All agreements of the New Guarantor in this
Third Supplemental Indenture shall bind its successors except as provided in
the Indenture.  All agreements of the
Trustee in this Third Supplemental Indenture shall bind its successors.  Section 2.9.  Certain Duties and Responsibilities of the
Trustee.  In entering into this Third
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 Third 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 Third
Supplemental Indenture or the Securities.  Section 2.11.  Multiple Originals.  The parties may sign any number of copies of
this Third 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 Third 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 Third Supplemental
Indenture to be duly executed as of the date first written above.  New GuarantorsBMCA
  Acquisition Inc.BMCA
  Acquisition Sub Inc.BMCA
  Gainesville LLCBy:
  /s/ John MaitnerName:    John
  MaitnerTitle:      Vice
  President, TreasurerCompanyBUILDING
  MATERIALSCORPORATION
  OF AMERICABy:
  /s/ John MaitnerName:    John
  MaitnerTitle:      Vice
  President, Treasurer


Existing GuarantorsBUILDING MATERIALS
  INVESTMENTCORPORATIONBMCA INSULATION PRODUCTS
  INC.BUILDING MATERIALSMANUFACTURING CORPORATIONDUCTWORK MANUFACTURINGCORPORATIONGAF MATERIALS CORPORATION(CANADA)GAF PREMIUM PRODUCTS INC.GAF REAL PROPERTIES, INC.GAFTECH CORPORATIONLL BUILDING PRODUCTS INC.PEQUANNOCK VALLEY CLAIMSERVICE COMPANY, INC.SOUTH PONCA REALTY CORP.BMCA QUAKERTOWN INC.WIND GAP REAL PROPERTYACQUISITION CORP.HBP ACQUISITION LLCBMCA NEWCO INC.By:
  /s/ John MaitnerName:    John
  MaitnerTitle:      Vice
  President, Treasurer


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