Exhibit 32.1

CERTIFICATION OF THE CHIEF EXECUTIVE OFFICER AND CHIEF FINANCIAL OFFICER
PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO SECTION 906 OF
THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of International Aluminum Corporation (the “Company”) on Form 10-Q for the period ending September 30, 2005, as filed with the Securities and Exchange Commission (the “Report”), we the undersigned certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to our 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.

Date:    November 7, 2005	RONALD L. RUDY
	Ronald L. Rudy
	President and
	Chief Executive Officer
Date:    November 7, 2005	MITCHELL K. FOGELMAN
	Mitchell K. Fogelman
	Senior Vice President—Finance
	and Chief Financial Officer

19