<PAGE>

         AMENDMENT No. 1, dated as of January 1, 2000, to AMENDED AND RESTATED
MANAGEMENT AGREEMENT, dated as of January 1, 1999 (the "Agreement"), by and
among GAF Corporation ("GAF"), G-I Holdings Inc. ("G-I Holdings"), G Industries
Corp. ("Industries"), Merick Inc. ("Merick"), GAF Fiberglass Corporation
(formerly known as GAF Chemicals Corporation) ("GFC"), International Specialty
Products Inc. (formerly known as ISP Holdings Inc.) ("New ISP"), GAF Building
Materials Corporation ("Building Materials"), GAF Broadcasting Company, Inc.
("Broadcasting"), Building Materials Corporation of America ("BMCA"), and ISP
Opco Holdings Inc. (the "Company"), as assignee of International Specialty
Products Inc.

         WHEREAS, in accordance with Section 7 of the Agreement, the parties
desire to adjust the management fees payable to the Company under the Agreement,
effective January 1, 2000, in order to reflect the costs to the Company of
providing services thereunder and the costs to a subsidiary of G-I Holdings for
providing certain office space to a subsidiary of the Company; and

         WHEREAS, the parties desire to extend the term of the Agreement;

         NOW, THEREFORE, the parties hereby amend the Agreement as follows:

         1.       Section 1 of the Agreement is hereby amended to extend the
Term until December 31, 2000.

         2.       Section 3 of the Agreement is amended to read in its
entirety as follows:

                  "In consideration of the Company providing Services hereunder,
                  (i) each of the corporations listed below shall pay to the
                  Company a management fee (the "Management Fee") at the
                  following respective rates for the year ending December 31,
                  2000: BMCA (on behalf of itself and its subsidiaries) -
                  $3,707,000; G-I Holdings (on behalf of itself and its
                  subsidiaries other than BMCA and BMCA's subsidiaries) -
                  $608,000 and New ISP - $109,463; and (ii) BMCA shall pay to
                  the Company a fee for the Company's provision to BMCA of
                  treasury, acquisition and investment management services
                  ("Financial Services Fee") at the annual rate of $1,120,000
                  for the year ended December 31, 2000. The Management Fee and
                  the Financial Services Fee shall be payable quarterly in
                  arrears.


<PAGE>





                  In addition to the Management Fee and the Financial Services
                  Fee, BMCA shall pay to a wholly-owned subsidiary of the
                  Company sublease payments pursuant to and in accordance with
                  the Sublease between BMCA and such subsidiary, the form of
                  which is attached as Exhibit A hereto and made a part hereof.

                  The Company, on behalf of its subsidiary as tenant under the
                  Lease attached hereto as Exhibit B and made a part hereof (the
                  "Lease), shall pay or cause to be paid to G-I Holdings the
                  lease payments due and payable under the Lease, as the Company
                  shall be reimbursed by such subsidiary for all such lease
                  payments made on its behalf. Such lease payments shall be paid
                  to G-I Holdings by way of offsetting the Management Fee and
                  other amounts due and payable to the Company by G-I Holdings
                  on behalf of itself and its subsidiaries (including the
                  landlord under the Lease) under the Agreement.

         3.       In all other respects, the Agreement as previously amended
shall remain in full force and effect.

         4.       This Amendment is subject to the approval of the Board of
Directors of the Company.




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<PAGE>



         IN WITNESS WHEREOF, the parties have executed this Amendment on the
date and year first above written.

<TABLE>
<S>                                                              <C>
     GAF CORPORATION                                                   G-I HOLDINGS INC.

By:  /s/ Susan B. Yoss                                            By:  /s/ Susan B. Yoss
     -----------------                                                 -----------------
Name:  Susan B. Yoss                                              Name:  Susan B. Yoss
Title: Senior Vice President,                                     Title: Senior Vice President,
       Chief Financial Officer and                                       Chief Financial Officer and
       Treasurer                                                         Treasurer

     G INDUSTRIES CORP.                                                MERICK INC.

By:  /s/ Susan B. Yoss                                            By:  /s/ Susan B. Yoss
     -----------------                                                 -----------------
Name:  Susan B. Yoss                                              Name:  Susan B. Yoss
Title: Senior Vice President,                                     Title: Senior Vice President and
       Chief Financial Officer and                                       Treasurer
       Treasurer

     GAF FIBERGLASS CORPORATION                                   INTERNATIONAL SPECIALTY PRODUCTS INC.

By:  /s/ Susan B. Yoss                                            By:  /s/ Randall R. Lay
     -----------------                                                 ------------------
Name:  Susan B. Yoss                                              Name:  Randall R. Lay
Title: Senior Vice President,                                     Title: Executive Vice President and
       Chief Financial Officer and                                       Chief Financial Officer
       Treasurer

GAF BUILDING MATERIALS CORPORATION                                GAF BROADCASTING COMPANY, INC.

By:  /s/ Susan B. Yoss                                            By:  /s/ Susan B. Yoss
     -----------------                                                 -----------------
Name:  Susan B. Yoss                                              Name:  Susan B. Yoss
Title: Senior Vice President,                                     Title: Senior Vice President and
       Chief Financial Officer and                                       Treasurer
       Treasurer

BUILDING MATERIALS CORPORATION                                        ISP OPCO HOLDINGS INC.
OF AMERICA

By:  /s/ William C. Lang                                          By:  /s/ Randall R. Lay
     -------------------                                               -------------------
Name:  William C. Lang                                            Name:  Randall R. Lay
Title: Executive Vice President,                                  Title: Executive Vice President and
       Chief Financial Officer and                                       Chief Financial Officer
       Chief Administrative Officer
</TABLE>

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