Owens Corning

To the Board of Directors and Stockholders of Owens Corning

Opinions on the Financial Statements and Internal Control over Financial Reporting

We have audited the accompanying consolidated balance sheets of Owens Corning and its subsidiaries (the "Company") as of December 31, 2024 and 2023, and the related consolidated statements of earnings, of comprehensive earnings, of stockholders’ equity and of cash flows for each of the three years in the period ended December 31, 2024, including the related notes (collectively referred to as the "consolidated financial statements"). We also have audited the Company's internal control over financial reporting as of December 31, 2024, based on criteria established in Internal Control - Integrated Framework(2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO).

In our opinion, the consolidated financial statements referred to above present fairly, in all material respects, the financial position of the Company as of December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2024 in conformity with accounting principles generally accepted in the United States of America. Also in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2024, based on criteria established in Internal Control - Integrated Framework(2013) issued by the COSO.

Basis for Opinions

The Company's management is responsible for these consolidated financial statements, for maintaining effective internal control over financial reporting, and for its assessment of the effectiveness of internal control over financial reporting, included in the accompanying Management’s Report on Internal Control Over Financial Reporting. Our responsibility is to express opinions on the Company’s consolidated financial statements and on the Company's internal control over financial reporting based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud, and whether effective internal control over financial reporting was maintained in all material respects.

Our audits of the consolidated financial statements included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the consolidated financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements. Our audit of internal control over financial reporting included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, and testing and evaluating the design and operating effectiveness of internal control based on the assessed risk. Our audits also included performing such other procedures as we considered necessary in the circumstances. We believe that our audits provide a reasonable basis for our opinions.

As described in Management’s Report on Internal Control Over Financial Reporting, management has excluded Masonite International Corporation from its assessment of internal control over financial reporting as of December 31, 2024 because it was acquired by the Company in a purchase business combination during 2024. We have also excluded Masonite International Corporation from our audit of internal control over financial reporting. Masonite International Corporation is a wholly-owned subsidiary whose total assets and total revenues excluded from management’s assessment and our audit of internal control over financial reporting represent 11% and 13%, respectively, of the related consolidated financial statement amounts as of and for the year ended December 31, 2024.

Definition and Limitations of Internal Control over Financial Reporting

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (i) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (ii) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (iii) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Critical Audit Matters

The critical audit matters communicated below are matters arising from the current period audit of the consolidated financial statements that were communicated or required to be communicated to the audit committee and that (i) relate to accounts or disclosures that are material to the consolidated financial statements and (ii) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matters below, providing separate opinions on the critical audit matters or on the accounts or disclosures to which they relate.

Acquisition of Masonite – Valuation of Certain Customer Relationships

As described in Notes 1 and 7 to the consolidated financial statements, on May 15, 2024, the Company completed the acquisition of Masonite for a total purchase price of $3.2 billion. Of the acquired intangible assets, certain customer relationships made up the majority of total customer relationships recorded of $979 million. The fair value of customer relationships was determined using the multi-period excess earnings method. Key assumptions under this method are the revenue growth rate, adjusted EBITDA margin (including the adjusted terminal EBITDA margin), customer attrition rate, discount rate, tax rate and contributory asset charges.

The principal considerations for our determination that performing procedures relating to the valuation of certain customer relationships acquired in the acquisition of Masonite is a critical audit matter are (i) the significant judgment by management when developing the fair value estimate of the customer relationships acquired; (ii) a high degree of auditor judgment, subjectivity, and effort in performing procedures and evaluating management’s significant assumptions related to the revenue growth rates, adjusted terminal EBITDA margin, customer attrition rate, discount rate, tax rate and contributory asset charges; and (iii) the audit effort involved the use of professionals with specialized skill and knowledge.

Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our overall opinion on the consolidated financial statements. These procedures included testing the effectiveness of controls relating to the acquisition accounting, including controls over management’s valuation of certain customer relationships acquired. These procedures also included, among others, (i) reading the purchase agreement; (ii) testing management’s process for developing the fair value estimate of the customer relationships acquired; (iii) evaluating the appropriateness of the multi-period excess earnings method used by management; (iv) testing the completeness and accuracy of the underlying data used in the multi-period excess earnings method; and (v) evaluating the reasonableness of the significant assumptions used by management related to the revenue growth rates, adjusted terminal EBITDA margin, customer attrition rate, discount rate, tax rate, and contributory asset charges. Evaluating management’s assumptions related to the revenue growth rates, adjusted terminal EBITDA margin, and tax rate involved considering (i) the current and past performance of the Masonite business; (ii) the consistency with external market and industry data; and (iii) whether the assumptions were consistent with evidence obtained in other areas of the audit. Professionals with specialized skill and knowledge were used to assist in evaluating (i) the appropriateness of the multi-period excess earnings method and (ii) the reasonableness of the customer attrition rate, discount rate, and contributory asset charges assumptions.

Interim Goodwill Impairment Test – Composites Reporting Unit

As described in Notes 1 and 5 to the consolidated financial statements, the Company’s goodwill balance was $2.8 billion as of December 31, 2024, and the goodwill associated with the Composites reporting unit was $423 million. Management tests goodwill for impairment as of October 1 each year, or more frequently should circumstances change or events occur that would more likely than not reduce the fair value of a reporting unit below its carrying amount. Subsequent to the annual test for the Composites reporting unit, management performed an interim goodwill impairment test during the fourth quarter of 2024 primarily as a result of the progression of the strategic review of the glass reinforcements business, which resulted in no impairment for the reporting unit. Management estimates fair value using a discounted cash flow approach from the perspective of a market participant, as well as the market approach. Significant assumptions used to determine fair value of the Composites reporting unit are the revenue growth rates, earnings before interest and taxes (“EBIT”) margins, long-term growth rate, and the discount rate.

The principal considerations for our determination that performing procedures relating to the interim goodwill impairment test of the Composites reporting unit is a critical audit matter are (i) the significant judgment by management when developing the fair value estimate of the Composites reporting unit; (ii) a high degree of auditor judgment, subjectivity and effort in performing procedures and evaluating management’s significant assumptions in the discounted cash flow approach related to revenue growth rates, EBIT margins, the long-term growth rate and discount rate for a portion of the Composites reporting unit; and (iii) the audit effort involved the use of professionals with specialized skill and knowledge.

Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our overall opinion on the consolidated financial statements. These procedures included testing the effectiveness of controls relating to management’s goodwill impairment test, including controls over the valuation of the Composites reporting unit. These procedures also included, among others (i) testing management’s process for developing the fair value estimate; (ii) evaluating the appropriateness of the discounted cash flow and market approaches used by management; (iii) testing the completeness and accuracy of data used in the discounted cash flow and market approaches; and (iv) evaluating the reasonableness of the significant assumptions used by management related to the revenue growth rates, EBIT margins, long-term growth rate and discount rate for a portion of the Composites reporting unit. Evaluating management’s assumptions related to the revenue growth rates and EBIT margins for a portion of the Composites reporting unit involved evaluating whether the assumptions used by management were reasonable considering (i) the current and past performance of a portion of the Composites reporting unit; (ii) the consistency with external market and industry data; and (iii) whether the assumptions were consistent with evidence obtained in other areas of the audit. Professionals with specialized skill and knowledge were used to assist in evaluating (i) the appropriateness of the discounted cash flow and market approaches and (ii) the reasonableness of the long-term growth rate and discount rate assumptions.

/s/ PricewaterhouseCoopers LLP

Toledo, Ohio

February 24, 2025

We have served as the Company’s auditor since 2002.