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                                                                     EXHIBIT 4.2


                      SECOND AMENDMENT TO RIGHTS AGREEMENT

         Second Amendment (this "Amendment") dated as of April 28, 2000 to the
Rights Agreement dated as of August 19, 1997, between Cameron Ashley Building
Products, Inc., a Georgia corporation (the "Company") and SunTrust Bank,
Atlanta, as Rights Agent (as amended, the "Rights Agreement").

         WHEREAS, the Company previously entered into that certain Agreement and
Plan of Merger dated as of January 17, 2000 (as amended from time to time, the
"CBP Merger Agreement") among CBP Holdings, Inc., a Georgia corporation ("CBP
Holdings"), CBP Acquisition Corp., a Georgia corporation and a wholly owned
subsidiary of CBP Holdings ("CBP Acquisition Corp."), and the Company;

         WHEREAS, in connection with the CBP Merger Agreement, a First Amendment
to Rights Agreement (the "First Amendment") was entered into between the Company
and the Rights Agent;

         WHEREAS, the Company has this date terminated the CBP Merger Agreement
and entered into that certain Agreement and Plan of Merger dated as of the date
hereof (as amended from time to time, the "Guardian Merger Agreement") among
Guardian Fiberglass, Inc., a Delaware corporation ("Guardian"), CAB Merger
Corp., a Georgia corporation and wholly owned subsidiary of Guardian ("CAB
Merger Corp."), and the Company;

         WHEREAS, the Board of Directors of the Company believes that it is in
the best interests of the Company and its shareholders that the transactions
contemplated by the Guardian Merger Agreement be consummated on the terms set
forth in the Guardian Merger Agreement;

         WHEREAS, the Board of Directors of the Company desires to amend the
Rights Agreement such that (a) the First Amendment shall be null and void and
superseded by this Second Amendment and (b) the execution of the Guardian Merger
Agreement and the consummation of the transactions contemplated thereby will not
cause (i) Guardian, CAB Merger Corp. or their respective Affiliates or
Associates to become an Acquiring Person or (ii) a Distribution Date or a Stock
Acquisition Date to occur, irrespective of the number of securities owned by
them collectively or acquired pursuant to the Merger Agreement or the Tender and
Option Agreement as defined in the Merger Agreement (the" Tender Agreement");
and

         WHEREAS, Section 27 of the Rights Agreement authorizes the Board of
Directors of the Company and the Rights Agent to adopt this Amendment without
the approval of the Company's shareholders.

         NOW, THEREFORE, in consideration of the recitals (which are deemed to
be a part of this Amendment) and agreements contained herein, the parties hereto
agree to amend the Rights Agreement as follows:


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         SECTION 1. AMENDMENT TO RIGHTS AGREEMENT. The Rights Agreement is
hereby amended as follows:

         (a) The definition of "Acquiring Person" set forth in Section 1(a) is
hereby modified by and amended by adding the following sentence at the end
thereof:

             Notwithstanding any provision of this Agreement to the contrary,
             neither the (i) execution and delivery of the Agreement and Plan of
             Merger dated as of April 28, 2000 among Guardian Fiberglass, Inc.
             ("Guardian"), CAB Merger Corp. ("CAB Merger Corp.") and the Company
             (the "Merger Agreement'), (ii) the execution and delivery of the
             Tender Agreement, (iii) any agreement of Guardian, CAB Merger Corp.
             and their Affiliates and Associates to act together in connection
             therewith nor (iv) the consummation of the transactions
             contemplated thereby shall be deemed to cause Guardian, CAB Merger
             Corp. or their Affiliates or Associates to be an Acquiring Person.

         (b) The definition of "Exempt Person" set forth in Section 1(t) of the
Rights Agreement is hereby amended and restated to read in its entirety as
follows:

             (t) "Exempt Person" shall mean any of the following: (i) CGW
             Southeast Partners I, L.P., a Georgia limited partnership ("CGW");
             or (ii) Guardian Fiberglass, Inc., a Delaware corporation
             ("Guardian"); CAB Merger Corp., a Georgia corporation and a wholly
             owned subsidiary of Guardian ("CAB Merger Corp."); or any Affiliate
             or Associate of Guardian or CAB Merger Corp.

         (c) The definition of "Stock Acquisition Date" set forth in Section
1(mm) of the Rights Agreement is hereby modified and amended by adding the
following sentence at the end thereof:

             Notwithstanding any provision of this Agreement to the contrary,
             neither (i) the execution and delivery of the Merger Agreement or
             the Tender Agreement, (ii) the agreement of Guardian and its
             Affiliates and Associates to act together in connection therewith,
             nor (iii) the consummation of the transactions contemplated thereby
             shall be deemed to cause a Stock Acquisition Date.

         (d) Section 3(a) of the Rights Agreement is hereby modified and amended
by adding the following sentence at the end thereof:

             Notwithstanding any provision of this Agreement to the contrary,
             neither (i) the execution and delivery of the Merger Agreement or
             the Tender Agreement, the agreement of Guardian and its Affiliates
             and Associates to act together in connection therewith,


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             nor the consummation of the transactions contemplated thereby shall
             be deemed to cause a Distribution Date.

         (e) Section 7(a) of the Rights Agreement is hereby amended and restated
to read in its entirety as follows:

             (a) EXERCISE. Subject to Section 7(e) (Exercise of Rights; Purchase
             Price; Expiration Date of Rights - Termination of Acquiring
             Person's Rights), the registered holder of any Rights Certificate
             may exercise the Rights evidenced thereby (except as otherwise
             provided herein, including, without limitation, the restrictions on
             exercisability set forth in Section 9(c) (Reservation and
             Availability of Capital Stock - Registration under the Act),
             Section 11(a)(iii) (Adjustment of Purchase Price; Number and Kind
             of Shares or Number of Rights - Certain Adjustments), Section 23(a)
             (Redemption and Termination - Redemption), and Section 24(b)
             (Exchange - Effect of Exchange; Procedure)) in whole or in part at
             any time after the Distribution Date upon surrender of the Rights
             Certificate, with the form of election to purchase and the
             certificate on the reverse side thereof duly executed, to the
             Rights Agent at the principal office or offices of the Rights Agent
             designated for such purpose, together with payment of the aggregate
             Purchase Price with respect to the total number of one
             ten-thousandths of a share of Preferred Stock (or other securities,
             cash or other assets, as the case may be) as to which such
             surrendered Rights are then exercisable and an amount equal to any
             applicable transfer tax, at or prior to the earliest of (i) the
             Final Expiration Date, (ii) the Redemption Date, (iii) the
             expiration of the Rights pursuant to Section 13(d) (Consolidation,
             Merger or Sale or Transfer of Assets or Earning Power - Exceptions)
             or (iv) the time immediately prior to the first acquisition of
             shares of Common Stock pursuant to the Merger Agreement (the
             earliest of (i), (ii), (iii) and (iv) being herein referred to as
             the "Expiration Date"). The payment of the Purchase Price and the
             applicable transfer tax, if any (as such amount may be reduced
             pursuant to Section 11(a)(iii) (Adjustment of Purchase Price;
             Number and Kind of Shares or Number of Rights - Certain
             Adjustments)), may be made (x) in cash, (y) by certified check,
             cashier's check or money order payable to the order of the Company,
             or (z) by delivery of a certificate or certificates (with
             appropriate stock powers executed in blank attached thereto)
             evidencing a number of shares of Common Stock equal to the then
             Purchase Price divided by the closing price (as determined pursuant
             to Section 11(d) (Adjustment of Purchase Price; Number and Kind of
             Shares or Number of Rights - Current Market Price) per share of
             Common Stock on the Trading Day immediately


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             preceding the date of such exercise. In the event that the Company
             is obligated to issue other securities (including Common Stock) of
             the Company, pay cash and/or distribute other property pursuant to
             Section 11(a) the Company will make all arrangements necessary so
             that such other securities, cash and/or other property are
             available for distribution by the Rights Agent, if and when
             appropriate. The Company reserves the right to require prior to the
             occurrence of a Triggering Event that upon any exercise of Rights,
             a number of Rights be exercised so that only whole shares of
             Preferred Stock would be issued.

         (f) Section 30 of the Rights Agreement is hereby modified and amended
to add the following sentence at the end thereof:

             Nothing in this Agreement shall be construed to give any holder of
             Rights or any other Person any legal or equitable rights, remedy or
             claim under this Agreement in connection with any transactions
             contemplated by the Merger Agreement or the Tender Agreement.

         (g) The First Amendment is hereby revoked in its entirety.

SECTION 2. MISCELLANEOUS

         (a) Capitalized terms used and not otherwise defined herein shall have
the meaning assigned to such terms in the Rights Agreement.

         (b) The term "Agreement" as used in the Rights Agreement shall be
deemed to refer to the Rights Agreement as amended hereby and without regard to
the First Amendment.

         (c) This Amendment shall be effective as of the time immediately prior
to the execution and delivery of the Merger Agreement, and, except as set forth
herein, the Rights Agreement shall remain in full force and effect and shall be
otherwise unaffected hereby.

         (d) If any term, provision, covenant or restriction of this Amendment
is held by a court of competent jurisdiction or other authority to be invalid,
void or unenforceable, the other terms, provisions, covenants and restrictions
of this Amendment, and of the Rights Agreement shall remain in full force and
effect and shall in no way be affected, impaired or invalidated.

         (e) In all respects not inconsistent with this Amendment, the Rights
Agreement is hereby ratified, approved and confirmed. In executing and
delivering this Amendment, the Rights Agent shall be entitled to all of the
privileges and immunities afforded to the Rights Agent under the Rights
Agreement.

         (f) This Amendment may be executed in two or more counterparts, each of
which shall be deemed to be an original, but all of which together shall
constitute one and the same instrument.


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         (g) This Amendment shall be deemed to be a contract made under the laws
of the State of Georgia and for all purposes shall be governed by and construed
in accordance with the laws of the State of Georgia applicable to contracts to
be made and performed entirely within the State of Georgia.

         IN WITNESS WHEREOF, the parties have caused this Amendment to be duly
executed as of the day and year first above written.

<TABLE>
<S>                                            <C>
                                               CAMERON ASHLEY BUILDING
Attest:                                        PRODUCTS, INC.


By:    /s/ JOHN S. DAVIS                       By:   /s/ WALTER J. MURATORI
     ------------------------------------         ---------------------------------
Name:       John S. Davis                      Name:      Walter J. Muratori
Title:      Vice President - General                      President
            Counsel and Secretary



                                               SUNTRUST BANK, ATLANTA,
Attest:                                        as Rights Agent:


By:    /s/ SANDRA BENEFIELD                    By:   /s/ SUE HAMPTON
     ------------------------------------         ---------------------------------
Name:       Sandra Benefield                   Name:      Sue Hampton
      -----------------------------------            ------------------------------
Title:      Assistant Vice President           Title:     Assistant Vice President
      -----------------------------------            ------------------------------
</TABLE>


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