March 21, 1998


To:         Lundgren Bros. Construction, Inc.
            935 East Wayzata Boulevard
            Wayzata, Minnesota  55391
                                                                SECOND AMENDMENT
                                                             TO LETTER AGREEMENT
Ladies and Gentlemen:

         This second amendment to letter agreement (the "Amendment") is being
executed in order to amend certain of the terms and conditions contained in that
certain letter agreement dated March 21, 1996 (the "Letter Agreement") between
Lundgren Bros. Construction, Inc., a Minnesota corporation (the "Borrower"), and
U.S. Bank National Association, a national banking association, formerly known
as First Bank National Association (the "Bank"). In consideration of the mutual
agreements set forth herein, and for other good and valuable consideration, the
receipt and sufficiency of which is hereby acknowledged by the parties, the
Borrower and the Bank agree to further amend the Letter Agreement as follows:

         (a)      Paragraph 1 of the Letter Agreement, as previously amended, is
                  hereby deleted in its entirety and the following paragraph
                  inserted in lieu thereof effective as of March 21, 1998:

                                    "1. Subject to the provisions of this letter
                           agreement, at the Borrower's request, the Bank shall
                           make loans to the Borrower during the period from the
                           date of this letter agreement to May 31, 1999 in an
                           aggregate amount not exceeding $1,500,000.00 at any
                           time outstanding (the "Line of Credit"). The Line of
                           Credit is a revolving line of credit, and the
                           Borrower may borrow, prepay and reborrow under the
                           Line of Credit. The Borrower's obligation to repay
                           such loans and to pay interest and other charges,
                           fees and expenses thereon is evidenced by the
                           Borrower's Amendment and Restatement of Promissory
                           Note dated March 21, 1997, payable to the order of
                           the Bank in the principal amount of $1,500,000.00, as
                           amended by Second Amendment and Extension of
                           Promissory Note dated March 21, 1998 (together with
                           any additional amendments, extensions, renewals and
                           replacements thereof, called the "Revolving Note").
                           The Bank shall have no obligation to make any such
                           loan after the occurrence of any default or event of
                           default under the Revolving Note or any other
                           agreement of the Borrower with the Bank, or any other
                           event that would accelerate or allow the Bank to
                           accelerate payment of the








                           Revolving Note. The Borrower shall use all proceeds
                           of such loans solely for working capital of the
                           Borrower."

         (b)      Paragraph 4(b) of the Letter Agreement is hereby deleted in
                  its entirety and the following paragraph inserted in lieu
                  thereof effective as of March 21, 1998:

                           "`Determination Date' shall mean March 21, 1998, June
                           21, 1998, September 21, 1998, December 21, 1998 and
                           March 21, 1999."

         (c)      Exhibit A attached to the Letter Agreement is hereby deleted
                  in its entirety and replaced with Exhibit A attached hereto
                  and made a part hereof.

         (d)      Except as herein expressly modified, all of the terms and
                  conditions of the Letter Agreement shall remain in full force
                  and effect.

                               Sincerely,

                               U.S. BANK NATIONAL ASSOCIATION,
                               a national banking association, formerly known as
                               First Bank National Association


                               By:______________________________________________

                               Its:_____________________________________________


         Lundgren Bros. Construction, Inc. agrees to this Amendment to Letter
Agreement.

Executed as of March 21, 1998.

LUNDGREN BROS. CONSTRUCTION, INC.,
a Minnesota corporation


By:______________________________________
                                         
Its:_____________________________________




                                    EXHIBIT A

                        LUNDGREN BROS. CONSTRUCTION, INC.

                             BORROWER'S CERTIFICATE


         I, _______________________, the chief financial officer of Lundgren
Bros. Construction, Inc., a Minnesota corporation (the "Borrower"), pursuant to
the letter agreement dated March 21, 1996, as modified by amendments to letter
agreement dated March 21, 1997 and March 21, 1998, respectively (collectively,
the "Agreement"), hereby certify to U.S. Bank National Association, formerly
known as First Bank National Association (the "Bank"):

         1.       As of the close of business on ____________, 199___ (the most
                  recent Determination Date), the aggregate fair market value of
                  the Borrower's investments in account number 000303451 at FBS
                  Investment Services, Inc. was $_______________.

         2.       As of the date of this Certificate, no event has occurred
                  which constitutes a default or an event of default under the
                  Revolving Note (as defined in the Agreement), or an event that
                  would accelerate or allow the Bank to accelerate payment of
                  the Revolving Note, or would constitute any default or event
                  of default under the Revolving Note with notice or the passage
                  of time or both.

Date of Certificate:  __________________, 19_____





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                                            Signature