EXHIBIT 99.3           

CERTIFICATION OF CHIEF FINANCIAL OFFICER PURSUANT TO TITLE 18,

UNITED STATES CODE, SECTION 1350, AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Gibraltar Steel Corporation (the "Company") on Form 10-Q for the period ended March 31, 2003, as filed with the Securities and Exchange Commission on the date hereof (the "Report"), I, John E. Flint, Chief Financial Officer of the Company, certify, pursuant to Title 18, United States Code, Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to the best of my knowledge:

(1)    The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and
 

(2)    The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ John E. Flint

John E. Flint

Chief Financial Officer

May 14, 2003