<PAGE>


                                                                Exhibit 10.10(B)

                            LENDER JOINDER AGREEMENT

     THIS LENDER JOINDER AGREEMENT (this "Joinder"), dated as of May 22, 2003,
is executed by COMMERCEBANK, N.A. (the "Additional Lender") in favor of HUGHES
SUPPLY, INC., a Florida corporation (the "Borrower"), and SUNTRUST BANK, a
Georgia banking corporation, as administrative agent (the "Administrative
Agent") for the lenders (the "Lenders") from time to time party to the Revolving
Credit Agreement, dated as of March 26, 2003, among the Borrower, the Lenders
and the Administrative Agent (as amended, restated, supplemented or otherwise
modified from time to time, the "Credit Agreement"; capitalized terms used
herein and not otherwise defined shall have the meanings assigned to such terms
in the Credit Agreement).

                                    RECITALS

     A. Pursuant to Section 2.4(a) of the Credit Agreement, the Borrower has
elected to increase the Aggregate Revolving Commitment Amount from $252,500,000
to an amount not to exceed $300,000,000, and the Lenders party to the Credit
Agreement on the Closing Date have declined to increase their Revolving
Commitments.

     B. The Additional Lender has agreed to provide a Revolving Commitment to
the Borrower in the amount of $15,000,000 (the "Additional Lender Commitment
Amount") in accordance with the terms of Section 2.4 of the Credit Agreement.

     NOW, THEREFORE, the Additional Lender agrees as follows:

     SECTION 1. Joinder. By its signature below, the Additional Lender hereby
joins the Credit Agreement as a Lender, and establishes a Revolving Commitment
to the Borrower in the amount of the Additional Lender Commitment Amount. The
Additional Lender shall be a party to, and bound by, the Credit Agreement with
the same force and effect as if the Additional Lender had become a Lender on the
Closing Date.

     SECTION 2. Representations and Warranties. The Additional Lender represents
and warrants to the Administrative Agent and the Borrower that this Joinder has
been duly authorized, executed and delivered by it and that the Credit
Agreement, as modified by this Joinder, constitutes the legal, valid and binding
obligation of the Additional Lender, enforceable against it in accordance with
its terms.

     SECTION 3. Effectiveness; Automatic Increase. This Joinder shall become
effective (i) when it shall have been accepted by the Borrower and the
Administrative Agent and (ii) upon receipt by the Additional Lender of an
upfront fee in the amount of $22,500, at which time this Joinder shall be deemed
to be a part of and shall be subject to all the terms and conditions of the
Credit Agreement. Upon the acceptance of this Joinder by the Administrative
Agent, the Aggregate Revolving Commitment Amount shall automatically be
increased by an amount equal to the Additional Lender Commitment Amount and
Annex I of the Credit Agreement shall automatically be

<PAGE>


deemed amended to reflect the Revolving Commitment of the Additional Lender
committed hereunder.

     SECTION 4. Lack of Reliance on the Administrative Agent. The Additional
Lender acknowledges that it has, independently and without reliance upon the
Administrative Agent or any other Lender and based on such documents and
information as it has deemed appropriate, made its own credit analysis and
decision to enter into this Joinder and become a Lender under the Credit
Agreement. The Additional Lender acknowledges that it will, independently and
without reliance upon the Administrative Agent or any other Lender and based on
such documents and information as it has deemed appropriate, continue to make
its own decisions in taking or not taking any action under or based on this
Joinder, any related agreement or any document furnished hereunder or
thereunder.

     SECTION 5. Foreign Lenders. To the extent that the Additional Lender is a
Foreign Lender, it certifies that it has delivered all applicable forms and
performed all other actions required under Section 2.21(e) of the Credit
Agreement.

     SECTION 6. Governing Law. THIS JOINDER AND THE RIGHTS AND OBLIGATIONS OF
THE PARTIES HEREUNDER SHALL BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY THE
LAW (WITHOUT GIVING EFFECT TO THE CONFLICT OF LAW PRINCIPLES THEREOF) OF THE
STATE OF GEORGIA.

     SECTION 7. Execution in Counterparts. This Joinder may be executed in any
number of counterparts, each of which when so executed shall be deemed to be an
original and all of which taken together shall constitute one and the same
agreement.

     SECTION 8. Notices to Additional Lender. All communications and notices to
the Additional Lender shall be given to it at the address set forth under its
signature below.

                               [Signatures Follow]

<PAGE>

     IN WITNESS WHEREOF, the Additional Lender has duly executed this Joinder as
of the day and year first above written.

                                      ADDITIONAL LENDER:

                                      COMMERCEBANK, N.A.


                                      By /s/ Alan Hills
                                         ---------------------------------------
                                         Name: Alan Hills
                                         Title: Vice President

                                      Address for Notices:
                                      CommerceBank, N.A.
                                      220 Alhambra Circle, 11th Floor
                                      Coral Gables, FL 33134
                                      Attn: Maria Rosales or Jonathan Simoens
                                      Telecopy Number: 305-460-8637/8797
                                      Email: mrosales@commercebankfl.com or
                                             Jsimoens@commercebankfl.com

Acknowledged and Agreed to:

HUGHES SUPPLY, INC.
as Borrower


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


SUNTRUST BANK,
as Administrative Agent


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

<PAGE>

     IN WITNESS WHEREOF, the Additional Lender has duly executed this Joinder as
of the day and year first above written.

                                      ADDITIONAL LENDER:

                                      COMMERCEBANK, N.A.


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

                                      Address for Notices:
                                      CommerceBank, N.A.
                                      220 Alhambra Circle, 11th Floor
                                      Coral Gables, FL 33134
                                      Attn: Maria Rosales or Jonathan Simoens
                                      Telecopy Number: 305-460-8637/8797
                                      Email: mrosales@commercebankfl.com or
                                             Jsimoens@commercebankfl.com

Acknowledged and Agreed to:

HUGHES SUPPLY, INC.
as Borrower


By /s/ Jeffrey S. Leonard
   ---------------------------------
   Name: Jeffrey S. Leonard
   Title:


SUNTRUST BANK,
as Administrative Agent


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

<PAGE>

     IN WITNESS WHEREOF, the Additional Lender has duly executed this Joinder as
of the day and year first above written.

                                      ADDITIONAL LENDER:

                                      COMMERCEBANK, N.A.


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

                                      Address for Notices:
                                      CommerceBank, N.A.
                                      220 Alhambra Circle, 11th Floor
                                      Coral Gables, FL 33134
                                      Attn: Maria Rosales or Jonathan Simoens
                                      Telecopy Number: 305-460-8637/8797
                                      Email: mrosales@commercebankfl.com or
                                             Jsimoens@commercebankfl.com

Acknowledged and Agreed to:

HUGHES SUPPLY, INC.
as Borrower


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


SUNTRUST BANK,
as Administrative Agent


By: /s/ William C. Barr, III
    --------------------------------
    William C. Barr, III
    Director

<PAGE>

                              REVOLVING CREDIT NOTE

$15,000,000                                                         May 22, 2003

     FOR VALUE RECEIVED, the undersigned, HUGHES SUPPLY, INC. a Florida
corporation (the "Borrower"), hereby promises to pay to COMMERCEBANK, N.A. (the
"Lender") or its registered assigns, at the office of SunTrust Bank ("SunTrust")
at 303 Peachtree St., N.E., Atlanta, Georgia 30308, on the Revolving Commitment
Termination Date (as defined in the Revolving Credit Agreement dated as of March
26, 2003, (as the same may be amended, restated, supplemented or otherwise
modified from time to time, the "Credit Agreement"), among the Borrower, the
Lenders from time to time party thereto and SunTrust as the Administrative Agent
for the Lenders), the lesser of the principal sum of FIFTEEN MILLION AND NO/100
DOLLARS and the aggregate unpaid principal amount of all Revolving Loans made by
the Lender to the Borrower pursuant to the Credit Agreement, in lawful money of
the United States of America in immediately available funds, and to pay interest
from the date hereof on the principal amount thereof from time to time
outstanding, in like funds, at said office, at the rate or rates per annum and
payable on such dates as provided in the Credit Agreement. In addition, should
legal action or an attorney-at-law be utilized to collect any amount due
hereunder, the Borrower further promises to pay all costs of collection,
including the reasonable attorneys' fees of the Lender actually incurred.

     Upon the occurrence of an Event of Default, the Borrower promises to pay
interest, on demand, at a rate or rates provided in the Credit Agreement.

     All borrowings evidenced by this Revolving Credit Note and all payments and
prepayments of the principal hereof and the date thereof shall be endorsed by
the holder hereof on the schedule attached hereto and made a part hereof or on a
continuation thereof which shall be attached hereto and made a part hereof, or
otherwise recorded by such holder in its internal records; provided, that the
failure of the holder hereof to make such a notation or any error in such
notation shall not affect the obligations of the Borrower to make the payments
of principal and interest in accordance with the terms of this Revolving Credit
Note and the Credit Agreement.

     This Revolving Credit Note is issued in connection with, and is entitled to
the benefits of, the Credit Agreement which, among other things, contains
provisions for the acceleration of the maturity hereof upon the happening of
certain events, for prepayment of the principal hereof prior to the maturity
hereof and for the amendment or waiver of certain provisions of the Credit
Agreement, all upon the terms and conditions therein specified. THIS REVOLVING
CREDIT NOTE SHALL BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY THE LAWS OF
THE STATE OF GEORGIA AND ANY APPLICABLE LAWS OF THE UNITED STATES OF AMERICA.

<PAGE>

                                      HUGHES SUPPLY, INC., a Florida corporation


                                      By: /s/ Jeffrey S. Leonard
                                          --------------------------------------
                                          Name: Jeffrey S. Leonard
                                          Title:

<PAGE>

                               LOANS AND PAYMENTS

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                                                  Unpaid
                                                Principal        Name of Person
            Amount and        Payments of       Balance of           Making
Date       Type of Loan        Principal           Note             Notation
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                              COMPETITIVE BID NOTE

$50,000,000                                                        May 22, 2003

     FOR VALUE RECEIVED, the undersigned, HUGHES SUPPLY, INC. a Florida
corporation (the "Borrower"), hereby promises to pay to COMMERCEBANK, N.A. (the
"Lender") or its registered assigns, at the office of SunTrust Bank ("SunTrust")
at 303 Peachtree Street, N.E., Atlanta, Georgia 30308, or at such other place as
the holder hereof may designate in writing to the Borrower, on the Revolving
Commitment Termination Date (as defined in the Revolving Credit Agreement dated
as of March 26, 2003 (as the same may be amended, restated, supplemented or
otherwise modified from time to time, the "Credit Agreement"), among the
Borrower, the Lenders from time to time party thereto and SunTrust, as
Administrative Agent for the Lenders), the lesser of the principal sum of FIFTY
MILLION AND N0/100 DOLLARS ($50,000,000) and the aggregate unpaid principal
amount of all Competitive Bid Loans made by the Lender to the Borrower pursuant
to the Credit Agreement, in lawful money of the United States of America in
immediately available funds, and to pay interest from the date hereof on the
principal amount thereof from time to time outstanding, in like funds, at said
office, at the rate or rates per annum and payable on such dates as provided in
the Credit Agreement. In addition, should legal action or an attorney-at-law be
utilized to collect any amount due hereunder, the Borrower further promises to
pay all costs of collection, including the reasonable attorneys' fees of the
Lender actually incurred.

     Upon the occurrence of an Event of Default, the Borrower promises to pay
interest, on demand, at the Default Rate (as defined in the Credit Agreement) on
the terms and conditions set forth in the Credit Agreement.

     All borrowings evidenced by this Competitive Bid Note and all payments and
prepayments of the principal hereof and the date thereof shall be endorsed by
the holder hereof on the schedule attached hereto and made a part hereof or on a
continuation thereof which shall be attached hereto and made a part hereof, or
otherwise recorded by such holder in its internal records; provided, that the
failure of the holder hereof to make such a notation or any error in such
notation shall not affect the obligations of the Borrower to make the payments
of principal and interest in accordance with the terms of this Competitive Bid
Note and the Credit Agreement.

     This Competitive Bid Note is issued in connection with, and is entitled to
the benefits of, the Credit Agreement which, among other things, contains
provisions for the acceleration of the maturity hereof upon the happening of
certain events, for prepayment of the principal hereof prior to the maturity
hereof and for the amendment or waiver of certain provisions of the Credit
Agreement, all upon the terms and conditions therein specified.

<PAGE>

THIS COMPETITIVE BID NOTE SHALL BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY
THE LAWS OF THE STATE OF GEORGIA AND ANY APPLICABLE LAWS OF THE UNITED STATES OF
AMERICA.

                                      HUGHES SUPPLY, INC., a Florida corporation


                                      By: /s/ Jeffrey S. Leonard
                                          --------------------------------------
                                          Name: Jeffrey S. Leonard
                                          Title:

<PAGE>

                               LOANS AND PAYMENTS

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                                                  Unpaid
                                                 Principal       Name of Person
            Amount and        Payments of       Balance of           Making
Date       Type of Loan        Principal           Note             Notation
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