Document:

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                                                                     Exhibit 4.3

                                 AMENDMENT NO. 1
                                       TO
                                CREDIT AGREEMENT

         THIS AMENDMENT NO. 1 TO THE CREDIT AGREEMENT (the "Amendment") is made
as of March 3, 2000 by and among HUTTIG BUILDING PRODUCTS, INC. (the
"Borrower"), the financial institutions listed on the signature pages hereof
(the "Lenders") and BANK ONE, NA (having its principal office in Chicago,
Illinois) in its individual capacity as a Lender and in its capacity as
contractual representative (the "Agent") under that certain Credit Agreement
dated as of December 16, 1999 by and among the Borrower, the financial
institutions party thereto and the Agent (the "Credit Agreement"). Defined terms
used herein and not otherwise defined herein shall have the meanings given to
them in the Credit Agreement.

                                   WITNESSETH:

         WHEREAS, the Borrower, the Lenders and the Agent are parties to the
Credit Agreement; and

         WHEREAS, the Borrower, the requisite number of Lenders under
Section 9.3 of the Credit Agreement and the Agent have agreed to amend the
Credit Agreement on the terms and conditions set forth herein;

         NOW, THEREFORE, in consideration of the premises set forth above, the
terms and conditions contained herein, and other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties hereto have agreed to the following amendments to the Credit Agreement:

         1. AMENDMENTS TO THE CREDIT AGREEMENT. Effective as of March 3, 2000
and subject to the satisfaction of the conditions precedent set forth in Section
2 below, the Credit Agreement is hereby amended as follows:

                  1.1. Section 2.14(D) of the Credit Agreement is amended to
         delete clauses (ii) and (iii) thereof in their entirety and to
         substitute the following therefor:

                           (ii) The (a) Applicable Eurodollar Margin shall be
                  the greater of (1) 1.75% per annum and (2) the margin over
                  LIBOR or the applicable eurodollar rate charged with respect
                  to the Interim Financing (as defined in Section 7.3(A)(ix)
                  below); (b) the Applicable Floating Rate Margin shall be equal
                  to the Applicable Eurodollar Rate Margin minus 1.00%; (c) the
                  Applicable L/C Fee Percentage shall be equal to the Applicable
                  Eurodollar Margin; and (d) the Applicable Commitment Fee
                  Percentage shall be equal to 0.375% per annum.

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                  1.2. Section 7.2 of the Credit Agreement is amended to add new
         Section 7.2(M) as follows:

                           (M) In the event the Borrower shall have not
                  refinanced the Obligations (including providing cash
                  collateral for all L/C Obligations or a back-to-back letter of
                  credit from an issuer reasonably acceptable to the Issuing
                  Bank) and terminates this Agreement not later than the
                  maturity date of the Interim Financing (as defined in Section
                  7.3(A)(ix) hereof), (i) Borrower shall, and shall cause each
                  of its Subsidiaries who are parties to the Subsidiary
                  Guaranty, (i )to promptly execute security agreements and
                  financing statements in forms reasonably acceptable to the
                  Agent and the Borrower granting to the Agent on behalf of the
                  Lenders a security interest in Borrower's and such
                  Subsidiaries' accounts receivable and inventory, and (ii)
                  notwithstanding the provisions of this Agreement, including
                  but not limited to Section 7.3(c) hereof, Borrower and such
                  Subsidiaries may, at the time of granting of the security
                  interests described in subpart (i) above, grant and perfect
                  pari passu liens and security interests in their respective
                  accounts receivable and inventory in favor of The Chase
                  Manhattan Bank, as agent for the benefit of the lenders under
                  the Interim Financing.

                  1.3. Section 7.3(A)(ix) of the Credit Agreement is hereby
         deleted in its entirety, and the following is substituted therefor:

                           (ix) short-term unsecured Indebtedness provided by
                  The Chase Manhattan Bank or one of its affiliates (and their
                  assignees) to the Borrower, the outstanding principal amount
                  of which shall not exceed $25,000,000 and the other terms and
                  conditions of which shall be substantially similar to the
                  Credit Agreement except that the maturity date thereof shall
                  be the date sixty calendar days after all conditions to the
                  effectiveness of Amendment No. 1 to this Credit Agreement have
                  been satisfied (the "INTERIM FINANCING");

                  1.4. Section 7.3(E) of the Credit Agreement is amended to
         delete clause (vi) therefrom in its entirety and to substitute the
         following therefor:

                           (vi) Contingent Obligations of Subsidiaries which are
                  Guarantors under the Guaranty consisting of the guaranty of
                  the Interim Financing,

                  1.5. Section 7.3 of the Credit Agreement is amended to add the
         following at the end thereof:

                           (S) Pari Passu Payments and Prepayments with Interim
                  Financing; No Reduction of Interim Financing. Without the
                  prior written consent of Agent and the Required Lenders, the
                  Borrower shall not (i) repay or prepay any amount outstanding
                  under the Interim Facility without making a simultaneous
                  ratable

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                  repayment or prepayment (based upon relative outstandings) of
                  the Revolving Credit Obligations and (ii) reduce the
                  commitment or otherwise take action the result of which would
                  be to reduce the aggregate amount available to the Borrower
                  under the Interim Facility to be less than $25,000,000.

                  1.6. Section 7.4(B) of the Credit Agreement is hereby deleted
         in its entirety, and the following is substituted therefor:

                           (B) Minimum Consolidated Net Worth. The Borrower
                  shall not permit its Consolidated Net Worth at any time to be
                  less than the sum of (a) $65,000,000 plus (b) fifty percent
                  (50%) of Net Income (if positive) earned in each fiscal
                  quarter calculated beginning with the fiscal quarter ending
                  March 31, 2000, plus (c) one-hundred percent (100%) of any
                  positive adjustment to stockholders' equity resulting from any
                  transaction involving any capital contribution to the Borrower
                  or the issuance by the Borrower or any Subsidiary of any
                  Capital Stock to the extent such capital contribution or any
                  other cash or other property received by the Borrower or such
                  Subsidiary from such issuance is used by the Borrower or any
                  Subsidiary to pay all or any part of the purchase price of any
                  Permitted Acquisition.

         2. CONDITIONS OF EFFECTIVENESS. The effectiveness of this Amendment is
subject to the conditions precedent that the Agent shall have received the
following documents:

                  (a)      duly executed originals of this Amendment from each
                           of the Borrower and the requisite number of Lenders
                           under Section 9.3 of the Credit Agreement;

                  (b)      duly executed originals of a Reaffirmation in the
                           form of Exhibit A attached hereto from each of
                           Rondels, Inc., a Washington corporation, CIPCO Inc.,
                           an Illinois corporation; Rugby USA, Inc., a Georgia
                           corporation, and Rugby Building Products, Inc., a
                           Delaware corporation; and

                  (c)      The Borrower shall have paid all amounts payable
                           under and pursuant to the terms of Section 10.7(A) of
                           the Credit Agreement and payable pursuant to the
                           separate fee agreement between the Borrower, Banc One
                           Capital Markets, Inc. and the Agent.

         3. REPRESENTATIONS AND WARRANTIES OF THE BORROWER. The Borrower hereby
represents and warrants as follows:

                  (a)      This Amendment and the Credit Agreement, as
                           previously executed and as amended hereby, constitute
                           legal, valid and binding obligations of the Borrower
                           and are enforceable against the Borrower in
                           accordance with their terms.

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                  (b)      Upon the effectiveness of this Amendment and after
                           giving effect hereto, (i) the Borrower hereby
                           reaffirms all covenants, representations and
                           warranties made in the Credit Agreement as amended
                           hereby, and agrees that all such covenants,
                           representations and warranties (other than covenants,
                           representations and warranties that are expressly
                           made as of a specific date) shall be deemed to have
                           been remade as of the effective date of this
                           Amendment and (ii) no Default or Unmatured Default
                           has occurred and is continuing.

                  (c)      The Borrower:

                           (i)      has received and has accepted a
                                    fully-underwritten commitment from The Chase
                                    Manhattan Bank (or one of its affiliates)
                                    for committed financing to be provided to
                                    the Borrower in an amount not less than
                                    $200,000,000 for the refinancing of the
                                    Obligations, which commitment contains only
                                    customary conditions precedent relating to
                                    credit facilities of this type;

                           (ii)     has reasonably determined that it is able to
                                    meet all of the conditions precedent
                                    contained in such commitment on or prior to
                                    the date sixty calendar days after all
                                    conditions to the effectiveness of this
                                    Amendment have been satisfied; and

                           (iii)    has provided or caused to be provided a true
                                    and accurate copy of such commitment letter
                                    and term sheet to the Agent and, other than
                                    a fee letter in connection therewith, has
                                    entered into no other agreements which alter
                                    the terms thereof.

         4. REFERENCE TO THE EFFECT ON THE CREDIT AGREEMENT.

                  (a)      Upon the effectiveness of Section 1 hereof, on and
                           after the date hereof, each reference in the Credit
                           Agreement (including any reference therein to "this
                           Credit Agreement," "hereunder," "hereof," "herein" or
                           words of like import referring thereto) or in any
                           other Loan Document shall mean and be a reference to
                           the Credit Agreement as amended hereby.

                  (b)      Except as specifically amended above, the Credit
                           Agreement and all other documents, instruments and
                           agreements executed and/or delivered in connection
                           therewith, shall remain in full force and effect, and
                           are hereby ratified and confirmed.

                  (c)      The execution, delivery and effectiveness of this
                           Amendment shall not, except as expressly provided
                           herein, operate as a waiver of any right, power or
                           remedy of the Agent or the Lenders, nor constitute a
                           waiver of

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                           any provision of the Credit Agreement or any other
                           documents, instruments and agreements executed and/or
                           delivered in connection therewith.

         5. GOVERNING LAW. THIS AMENDMENT SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE INTERNAL LAWS (INCLUDING 735 ILCS 105/5-1 ET SEQ., BUT
OTHERWISE WITHOUT REGARD TO THE CONFLICT OF LAW PROVISIONS) OF THE STATE OF
ILLINOIS.

         6. HEADINGS. Section headings in this Amendment are included herein for
convenience of reference only and shall not constitute a part of this Amendment
for any other purpose.

         7. COUNTERPARTS; FACSIMILE EFFECTIVENESS. This Amendment may be
executed by one or more of the parties to this Amendment on any number of
separate counterparts and all of said counterparts taken together shall be
deemed to constitute one and the same instrument. A facsimile signature page
hereto sent to the Agent or the Agent's counsel shall be effective as a
counterpart signature provided each party executing such a facsimile counterpart
agrees to deliver originals to the Agent thereof.

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         IN WITNESS WHEREOF, this Amendment has been duly executed as of the day
and year first above written.

HUTTIG BUILDING PRODUCTS, INC.

By: /s/ BARRY J. KULPA
    ---------------------------------
Name: Barry J. Kulpa
  Title: President and Chief Executive Officer

BANK ONE, NA
(Main Office Chicago),
as Agent and as Lender

By: /s/ NATHAN L. BLOCH
    ---------------------------------
Name: Nathan L. Bloch
  Title: First Vice President

THE CHASE MANHATTAN BANK,
as a Lender

By: /s/ ALAN J. ARIA
    ---------------------------------
Name: Alan J. Aria
  Title: Vice President

COMERICA BANK,
as a Lender

By: /s/ JEFFREY E. PECK
    ---------------------------------
Name: Jeffrey E. Peck
  Title: Vice President

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MERCANTILE BANK NATIONAL ASSOCIATION,
as a Lender

By: /s/ GERALD S. KIRK
    ---------------------------------
Name: Gerald S. Kirk
  Title: Vice President

FIRST UNION NATIONAL BANK,
as a Lender

By:
    ---------------------------------
Name:
  Title:

BANK OF NEW YORK,
as a Lender

By:
    ---------------------------------
Name:
  Title:

THE DAI-ICHI KANGYO BANK, LTD.,
as a Lender

By: /s/ NELSON Y. CHANG
    ---------------------------------
Name: Nelson Y. Chang
  Title: Assistant Vice President

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                                    EXHIBIT A

                                  REAFFIRMATION

         Each of the undersigned hereby acknowledges receipt of a copy of the
foregoing Amendment No. 1 to the Credit Agreement dated as of December 16, 1999
by and among HUTTIG BUILDING PRODUCTS, INC. (the "Borrower"), the financial
institutions from time to time party thereto (the "Lenders") and BANK ONE, NA
(having its principal office in Chicago, Illinois), in its individual capacity
as a Lender and in its capacity as contractual representative (the "Agent") (as
amended and as the same may be amended, restated, supplemented or otherwise
modified from time to time, the "Credit Agreement"), which Amendment No. 1 is
dated as of March 3, 2000 (the "Amendment"). Capitalized terms used in this
Reaffirmation and not defined herein shall have the meanings given to them in
the Credit Agreement. Without in any way establishing a course of dealing by the
Agent or any Lender, each of the undersigned reaffirms the terms and conditions
of the Guaranty and any other Loan Document executed by it and acknowledges and
agrees that such Guaranty and each and every such Loan Document executed by the
undersigned in connection with the Credit Agreement remains in full force and
effect and is hereby reaffirmed, ratified and confirmed. All references to the
Credit Agreement contained in the above-referenced documents shall be a
reference to the Credit Agreement as so modified by the Amendment and as the
same may from time to time hereafter be amended, modified or restated.

Dated: March 3, 2000
                                             RONDELS, INC.
                                             CIPCO INC.
                                             RUGBY USA, INC.
                                             RUGBY BUILDING PRODUCTS, INC.

                                             By /s/ Gregory D. Lambert
                                               ----------------------------
                                             Name: Gregory D. Lambert
                                             Title: Vice President<PAGE>   1
                                                                     Exhibit 4.4

Huttig promissory note in favor of certain of the lenders.

                           FORM OF REVOLVING LOAN NOTE

U.S. $[____________]
                                                               Chicago, Illinois
                                                               December 16, 1999

             FOR VALUE RECEIVED, the undersigned, Huttig Building Products,
Inc., a Delaware Corporation (the "Borrower"), HEREBY UNCONDITIONALLY PROMISES
TO PAY to the order of [____________________] (the "Lender") the principal sum
of [_________________________] AND NO/100 DOLLARS ($[________________]), or, if
less, the aggregate unpaid amount of all "Revolving Loans" (as defined in the
Credit Agreement referred to below) made by the Lender to the Borrower pursuant
to the "Credit Agreement" (as defined below), on the "Termination Date" (as
defined in the Credit Agreement) or on such earlier date as may be required by
the terms of the Credit Agreement. Capitalized terms used herein and not
otherwise defined herein are as defined in the Credit Agreement.

             The Borrower promised to pay interest on the unpaid principal
amount of each Revolving Loan made to it from the date of such Revolving Loan
until such principal amount is paid in full at a rate or rates per annum
determined in accordance with the terms of the Credit Agreement Interest
hereunder is due and payable at such times and on such dates as set forth in the
Credit Agreement.

             Both principal and interest are payable in Dollars to the Agent (as
defined below), to such account as the Agent may designate, in same day funds.
At the time of each Revolving Loan, and upon each payment or prepayment of
principal of each Revolving Loan, the Lender shall make a notation either on the
schedule attached hereto and made a part hereof, or in such Lender's own books
and records, in each case specifying the amount of such Revolving Loan, the
respective Interest Period thereof (in the case of Eurocurrency Rate Loans) or
the amount of principal paid or prepaid with respect to such Revolving Loan, as
applicable; provided that the failure of the Lender to make any such recordation
or notation shall not affect the Obligations of the Borrower hereunder or under
the Credit Agreement.

             This Revolving Loan Note is one of the promissory notes referred to
in, and is entitled to the benefits of, that certain Credit Agreement dated as
of December 16, 1999 among the Borrower, the financial institutions parties
thereto (the "Lenders"), and Banc One, NA (having its principal office in
Chicago, Illinois), individually and as agent (the "Agent") on behalf on the
Lenders, and Banc One Capital Markets, Inc., as lead arranger and sole book
runner (the "Lead Arranger and Sole Book Runner") on behalf of the Lenders (as
amended, restated, supplemented or modified from time to time, the "Credit
Agreement"). The Credit Agreement, among other things, (i) provides for the
making of Revolving Loans by the lender to the

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borrower under the Credit Agreement from time to time in an aggregate amount not
to exceed at any time outstanding the dollar amount first above mentioned, the
indebtedness of the Borrower resulting from each such Revolving Loan to it being
evidenced by this Revolving Loan Note, and (ii) contains provisions for
acceleration of the maturing hereof upon the happening of certain stated events
and also for prepayments of the principal hereof prior to the maturity hereof
upon the terms and conditions therein specified.

             Demand, presentment, protest and notice of nonpayment and protest
are hereby waived by the Borrower.

             Whenever in this Revolving Loan Note reference is made to the
Agent, the Lender or the Borrower, such reference shall be deemed to include, as
applicable, a reference to their respective successors and assigns. The
provisions of this Revolving Loan Note shall be binding upon and shall inure to
the benefit of said successors and assigns. The Borrower's successors and
assigns shall include, without limitation, a receiver, trustee or debtor in
possession of or for the Borrower.

             This Revolving Loan Note shall be interpreted, and the rights and
liabilities of the parties hereto determined, in accordance with the laws of the
State of Illinois.

                                              Huttig Building Products, Inc.

                                              By: /s/  Gregory Lambert
                                                 -------------------------------
                                                  Name:  Gregory Lambert
                                                  Title: Chief Financial Officer

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