GIBRALTAR INDUSTRIES, INC.

APPENDIX A - NON-GAAP MEASUREMENTSThe Company provides certain non-GAAP financial measures in this proxy statement that are not in accordance with GAAP.Adjusted Net Sales for MICP reflects the Company's net sales for the year ended December 31, 2025, as determined pursuant to GAAP, but excludes net sales attributable to the three metal roofing businesses acquired by the Company during the year ended December 31, 2025. Adjusted Net Income reflects the Company's income from continuing operations for the years ended December 31, 2025 and 2021, respectively, and net income for the years ended December 31, 2024, 2023, and 2022, respectively, as determined pursuant to GAAP, but excludes special charges consisting of restructuring costs (primarily associated with 80/20 simplification, lean initiatives, and/or discontinued products), senior leadership transition costs, acquisition related costs, intangible asset impairment and portfolio management activities. In addition, for 2025, Adjusted Net Income for ROIC excludes the net income attributable to the three metal roofing businesses acquired by the Company during the year ended December 31, 2025. These exclusions, along with other adjustments to other income below operating profit are excluded from Adjusted EPS and Adjusted EPS for MICP. ROIC is calculated as return divided by average invested capital, where return (Adjusted Net Income for ROIC plus interest, net of taxes, plus amortization, net of taxes, less dividends) is divided by the average of invested capital (funded debt less cash and marketable securities plus total stockholders’ equity) at the beginning and end of each calendar year in the performance period. DWC represents the 13-month average of accounts receivable and inventory less accounts payable for each month-end between December 31, 2024 through December 31, 2025 (excluding the three metal roofing businesses acquired during the year ended December 31, 2025), divided by the average daily Adjusted Net Sales for MICP (Adjusted Net Sales for MICP divided by 360 days).Free cash flow is defined as cash flows from operating activities, as determined pursuant to GAAP, minus purchases of property, plant, and equipment, net, as presented on a GAAP basis. Free cash flow as a percentage of net sales is calculated as free cash flow divided by net sales, as reported.Reconciliations of non-GAAP measures to their respective financial measures for the periods presented in this proxy statement are as follows for the year(s) end December 31, (dollar amounts in thousands, except per share data):

(1)Average adjusted net working capital represents the 13-month average of accounts receivable and inventory less accounts payable for each month end between December 31, 2024 through December 31, 2025 (excluding the metal roofing businesses acquired in 2025).

(1)Income from continuing operations, as reported for 2025 and 2021.(2)Average adjusted invested capital represents the 13-month average of total stockholders’ equity adjusted for special charges plus debt, minus cash for the periods ended December 31, 2025, 2024, 2023, 2022 and 2021, respectively.

In evaluating its business, the Company considers and uses free cash flow and free cash flow as a % of net sales as a supplemental measure of its operating performance. The following table summarizes free cash flow as a percentage of net sales for the year ended December 31, 2025 (dollar amounts in thousands):