Owens Corning and Masonite International Corporation (?Masonite?) announced that, in connection with the previously announced tender offer (the ?Tender Offer?) by Owens Corning and consent solicitation (the ?Consent Solicitation?) by Masonite, they have extended the expiration time with respect to the Tender Offer and Consent Solicitation from 5:00 p.m., New York City time, on May 13, 2024 to 5:00 p.m., New York City time, on May 14, 2024 (as the same may be further extended, the ?Expiration Time?), and that they have further extended the early participation deadline from 5:00 p.m., New York City time, on May 13, 2024 to 5:00 p.m., New York City time, on May 14, 2024 (as the same may be further extended, the ?Early Participation Deadline?). As previously announced, the requisite consents have been received to adopt certain amendments to the indenture (the ?Masonite Indenture?) governing the notes issued by Masonite subject to the Tender Offer and Consent Solicitation (the ?Masonite Notes?) to eliminate certain of the covenants, restrictive provisions and events of default from such indenture (the ?Proposed Amendments?). As previously announced, Owens Corning, MT Acquisition Co ULC, a wholly owned subsidiary of Owens Corning (?Purchaser?), and Masonite have entered into an Arrangement Agreement, dated as of February 8, 2024 (as it may be amended, the ?Arrangement Agreement?), providing for, among other things and subject to the terms and conditions of the Arrangement Agreement, the acquisition of all of Masonite?s issued and outstanding common shares by Purchaser (the ?Arrangement?).

Owens Corning and Masonite are making the Tender Offer and Consent Solicitation pursuant to the terms of and subject to the conditions set forth in the offer to purchase and consent solicitation statement dated April 15, 2024 (as amended to date, the ?Statement?), as amended by this news release, which are conditioned upon the consummation of the Arrangement and the satisfaction or waiver of other conditions described in the Statement. As a result, the Expiration Time may be extended one or more times. The settlement date for the Tender Offer and Consent Solicitation will be promptly after the Expiration Time.

Owens Corning and Masonite reserve the right to terminate, withdraw, amend or extend the Tender Offer and Consent Solicitation, including to extend the Expiration Time without extending the Early Participation Deadline. The deadline to withdraw Masonite Notes and revoke related consents tendered and delivered in the Tender Offer and Consent Solicitation was 5:00 p.m., New York City time, on April 26, 2024, which deadline has not been extended. Accordingly, previously tendered Masonite Notes and previously delivered consents may no longer be withdrawn or revoked, except where additional withdrawal rights are required by law.

As of 5:00 p.m., New York City time, on May 13, 2024, according to Global Bondholder Services Corporation, the Depositary and Information Agent for the Tender Offer and the Consent Solicitation, the principal amount of Masonite Notes set forth in the table below had been validly tendered and not validly withdrawn (and consents thereby deemed validly given and not validly revoked) in the Tender Offer and the Consent Solicitation. Title of Series: 5.375% Senior Notes due 2028. CUSIP /ISIN Nos.

of Masonite Notes: 144A CUSIP: 575385AD1, 144A ISIN: US575385AD19, Reg. S CUSIP: C5389UAL4, Reg. S ISIN: USC5389UAL47, Aggregate Principal Amount Outstanding: $500,000,000.

Masonite Notes Tendered and Consents Delivered at 5:00 p.m., New York City time, on May 13, 2024: Principal Amount: $471,270,000, Percentage: 94.25%. Masonite and the trustee under the Masonite Indenture have executed a supplemental indenture to the Masonite Indenture to effect the Proposed Amendments. However, the Proposed Amendments will not become operative unless and until (i) the Masonite Notes that are validly tendered (and not validly withdrawn) have been accepted for purchase and paid for by Owens Corning in accordance with the terms of the Tender Offer and Consent Solicitation, and (ii) the Arrangement has been consummated and all of the other conditions of the Consent Solicitation set forth in the Statement have been satisfied or waived by Owens Corning.