X0306 4 2019-05-01 0000007431 ARMSTRONG WORLD INDUSTRIES INC AWI 0001438149 McNamara Stephen F C/O ARMSTRONG WORLD INDUSTRIES, INC. 2500 COLUMBIA AVENUE, P. O. BOX 3001 LANCASTER PA 17603 1 Vice President and Controller Common Stock 2019-05-01 4 M 0 7778 21.95 A 18251 D Common Stock 2019-05-01 4 S 0 7778 87.26 D 10473 D Stock Options (Right to Buy) 21.95 2019-05-01 4 M 0 7778 0 D 2020-04-01 Common Stock 7778 0 D Grant has a graded vesting schedule. Date Exercisable will vary for each vesting tranche. All options are currently vested and exercisable. /s/Bryan Y.M. Tham, Attorney-in-fact 2019-05-02