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                                                                  Exhibit (a)(6)

                [Letterhead of Credit Suisse First Boston]


November 14, 1998



The Board of Directors
CalMat Co.
3200 San Fernando Road
Los Angeles, CA  90065

Dear Sirs and Madame:

You have asked us to advise you with respect to the fairness to the stockholders
of CalMat Co. (the "Company") from a financial point of view of the
consideration to be received by such stockholders pursuant to the terms of the
Agreement and Plan of Merger, dated as of November 14, 1998 (the "Acquisition
Agreement"), by and among the Company, Vulcan Materials Company, a New Jersey
corporation (the "Acquiror"), and ALB Acquisition Corporation (the "Sub"). The
Acquisition Agreement provides for a tender offer by Sub (the "Offer") for all
of the outstanding shares of common stock, par value $1.00 per share (the
"Common Stock"), including the associated common share purchase rights, of the
Company at a purchase price of $31.00 per share in cash. The Acquisition
Agreement further provides that following completion of the Offer, Sub will be
merged into the Company (the "Merger") pursuant to which the Company will become
a wholly owned subsidiary of the Acquiror and each outstanding share of Common
Stock of the Company will be converted into the right to receive $31.00 in cash.

In arriving at our opinion, we have reviewed certain publicly available business
and financial information relating to the Company, as well as the Acquisition
Agreement. We have also reviewed certain other information, including financial
forecasts, provided to us by the Company and have met with the Company's
management to discuss the business and prospects of the Company.

We have also considered certain financial and stock market data of the Company,
and we have compared this data with similar data for other publicly held
companies in businesses similar to the Company and we have considered the
financial terms of certain other business combinations and other transactions
which have recently been effected. We also considered such other information,
financial studies, analyses and investigations and financial, economic and
market criteria which we deemed relevant.

In connection with our review, we have not assumed any responsibility for
independent verification of any of the foregoing information and have relied on
its being complete and accurate in all material respects. With respect to the 
financial forecasts, we have assumed


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                                                               November 14, 1998
                                                                          Page 2


that they have been reasonably prepared on bases reflecting the best currently
available estimates and judgments of the Company's management as to the future
financial performance of the Company. In addition, we have not been requested to
make, and have not made, an independent evaluation or appraisal of the assets or
liabilities (contingent or otherwise) of the Company, nor have we been furnished
with any such evaluations or appraisals. Our opinion is necessarily based upon
financial, economic, market and other conditions as they exist and can be
evaluated on the date hereof. We were not requested to, and did not, solicit
third party indications of interest in acquiring all or any part of the Company.

We have acted as financial advisor to the Board of Directors of the Company in
connection with the Merger and will receive a fee for our services, a
significant portion of which is contingent upon the consummation of the Merger.

In the ordinary course of our business, we and our affiliates may actively trade
the debt and equity securities of both the Company and the Acquiror for our and
such affiliates' own accounts and for the accounts of customers and,
accordingly, may at any time hold a long or short position in such securities.

It is understood that this letter is for the information of the Board of
Directors of the Company in connection with its consideration of the Offer and
the Merger, does not constitute a recommendation to any stockholder as to
whether or not such stockholder should tender shares pursuant to the Offer or
how such stockholder should vote on the Merger and is not to be quoted or
referred to, in whole or in part, in any registration statement, prospectus or
proxy statement, or in any other document used in connection with the offering
or sale of securities, nor shall this letter be used for any other purposes,
without our prior written consent.

Based upon and subject to the foregoing, it is our opinion that, as of the date
hereof, the consideration to be received by the stockholders of the Company in
the Offer and the Merger is fair to such stockholders from a financial point of
view.

Very truly yours,

CREDIT SUISSE FIRST BOSTON CORPORATION


By: /s/ Steven Koch
    -----------------------
       Steven Koch
       Managing Director


