Owens Corning (OC) 10-Q 2023 Q2 Quarterly report

Exhibit 32.1

SECTION 1350 CERTIFICATION

In connection with the Quarterly Report on Form 10-Q of Owens Corning (the “Company”) for the quarterly period ended June 30, 2023 (the “Report”), I, Brian D. Chambers, certify, pursuant to 18 U.S.C. 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)Information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/  Brian D. Chambers 

Brian D. Chambers

Chief Executive Officer

July 26, 2023