Director William H. Osborne Receives 876 Restricted Stock Units in Armstrong World Industries

On June 12, 2026, Armstrong World Industries Inc. director William H. Osborne received an annual grant of 876 restricted stock units as part of the company's nonemployee Director Compensation Program. The units were granted under the 2016 Directors Stock Unit Plan and represent the equity portion of Osborne's retainer for Board service. The grant date fair value was calculated using the closing stock price of $154.21 per share on June 12, 2026. The restricted stock units vest on the earlier of: (1) the date of the next annual shareholders meeting following the grant; (2) the death or total and permanent disability of the director; or (3) the date of any Change in Control. Following this transaction, Osborne holds a total of 4,817 shares of common stock, including both vested and unvested units. The filing includes a power of attorney executed by Alan M. Kidd on June 15, 2026.