<PAGE>
                                                                  Exhibit (4)(j)

                            CERTIFICATE OF AMENDMENT
                                       TO
                            ARTICLES OF INCORPORATION
                                       OF
                                   LESCO, INC.

         William A. Foley, Chairman and Chief Executive Officer, and Patricia W.
Pribisko, Corporate Secretary, of LESCO, Inc., an Ohio corporation (the
"Corporation"), with its principal office located at 15885 Sprague Road,
Strongsville, Ohio 44136, do hereby certify that the following resolution
amending the Corporation's Articles of Incorporation was adopted by the Board of
Directors of the Corporation at a meeting of such Directors on February 22,
2002, and that pursuant to Article FOURTH of the Corporation's Articles of
Incorporation, and Section 1701.06(12) of the Ohio Revised Code, no shareholder
approval was required:

         WHEREAS, Article "FOURTH" of the Corporation's Articles of
         Incorporation now authorizes the Board of Directors to determine the
         terms of the Preferred Shares authorized by Article "FOURTH" without
         shareholder approval;

         RESOLVED: That Article "FOURTH" of the Corporation's Articles of
         Incorporation shall be amended by the addition thereto of the following
         Section 7:

                  Section 7. SERIAL PREFERRED SHARES. There is hereby
         established from among the Preferred Shares authorized above a series
         of Preferred Shares. The following provisions shall be applicable to
         the Serial Preferred Shares:

                           A. DESIGNATION. The shares of such series are
                  designated as "Series B Preferred Shares without par value"
                  (the "Series B Preferred Shares").

                           B. AUTHORIZED NUMBER OF SHARES. The authorized number
                  of Series B Preferred Shares is 5,000.

                           C. DIVIDENDS AND DISTRIBUTIONS. The annual dividend
                 rate of the Series B Preferred Shares shall be 7% of the
                 liquidation preference of $1,000 per share, payable solely in
                 shares of Series B Preferred Shares. The foregoing
                 notwithstanding, the Series B Preferred Shares shall be
                 entitled to receive, when, as, and if declared by the
                 Corporation's Board of Directors, dividends or distributions
                 payable in cash whenever the Corporation's Board of Directors
                 declares a dividend or distribution payable in cash on the
                 Corporation's Common Shares. For purposes of the foregoing
                 sentence, each Series B Preferred Share shall be treated the
                 same as one Common Share. Such dividends shall be cumulative
                 from the date of the initial issue of the Series B Preferred
                 Shares.

                           D. LIQUIDATION, DISSOLUTION OR WINDING UP. The amount
                  payable per Series B Preferred Share in the event of any
                  voluntary or involuntary liquidation,


<PAGE>

                  dissolution or winding up of the affairs of the Corporation
                  shall be $1,000, plus an amount equal to all dividends or
                  distributions accrued and unpaid thereon to the date of
                  payment.

                           E. REDEMPTION. The Series B Preferred Shares shall be
                  redeemable at the election of the Board of Directors.

                  IN WITNESS WHEREOF, we have executed this instrument in one or
more counterparts as of the 8th day of March 2002.



                                 ------------------------------
                                 William A. Foley
                                 Chairman and Chief Executive Officer



                                 -----------------------------
                                 Patricia W. Pribisko
                                 Corporate Secretary