Owens Corning

• 12 -

2. SEGMENT INFORMATION

As a result of our acquisition of Masonite International Corporation, which was completed on May 15, 2024, the Company now hasfour reportable segments: Roofing, Insulation, Doors, and Composites. Accounting policies for the segments are the same as those for the Company. The Company’sfour reportable segments are defined as follows:

Roofing – Within our Roofing segment, the Company manufactures and sells residential roofing shingles, oxidized asphalt materials, and roofing components primarily used in residential and commercial construction.

Insulation – Within our Insulation segment, the Company manufactures and sells thermal and acoustical batts, loose fill insulation, spray foam insulation, foam sheathing and accessories. It also manufactures and sells glass fiber pipe insulation, energy efficient flexible duct media, bonded and granulated stone wool insulation, cellular glass insulation, and foam insulation used in above- and below-grade construction applications.

Doors – Within our new Doors segment, the Company manufactures and sells interior and exterior doors and door systems primarily used in residential construction.

Composites – Within our Composites segment, the Company manufactures, fabricates and sells glass reinforcements in the form of fiber. Glass reinforcement materials are also used by the Composites segment to manufacture and sell high value applications in the form of non-wovens, fabrics and composite lumber.

The following tables show a disaggregation of our Net sales by segment and geographic region (in millions). Corporate eliminations (shown below) largely reflect intercompany sales from Composites to Roofing. External customer sales are attributed to geographic region based upon the location from which the product is sold to the external customer.

• 13 -

2. SEGMENT INFORMATION (continued)

Sales to major customers- The Company had two customers that exceeded 10% of consolidated net sales for the nine months ended September 30, 2024. The first customer, which is a customer of both the Roofing and Insulation segments, accounted for approximately 12% of the Company's consolidated net sales for the nine months ended September 30, 2024 and September 30, 2023. The second customer, which is a customer of the Roofing, Insulation and Doors segments, accounted for approximately 12% of the Company's consolidated net sales for the nine months ended September 30, 2024. This customer's sales did not exceed 10% during the nine months ended September 30, 2023.

EARNINGS BEFORE INTEREST AND TAXES

Earnings before interest and taxes (“EBIT”) by segment consist of net sales less related costs and expenses, and are presented on a basis that is used internally for evaluating segment performance. Certain items, such as general corporate expenses or income and certain other expense or income items, are excluded from the internal evaluation of segment performance. Accordingly, these items are not reflected in EBIT for our reportable segments and are included within Corporate, Other and Eliminations.

• 14 -

2. SEGMENT INFORMATION (continued)

The following table summarizes EBIT by segment (in millions):