Company Update

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549   FORM 8-K     CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): April 24, 2026     ARMSTRONG WORLD INDUSTRIES, INC. (Exact name of registrant as specified in its charter)     Pennsylvania 1-2116 23-0366390 (State or other jurisdiction of incorporation or organization) (Commission File Number) (IRS Employer Identification No.)           2500 Columbia Avenue P.O. Box 3001 Lancaster , Pennsylvania   17603 (Address of principal executive offices)   (Zip Code)   Registrant’s telephone number, including area code: (717) 397-0611 NA (Former name or former address if changed since last report.)     Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of ☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))   Securities registered pursuant to Section 12(b) of the Act: Title of each class   Trading Symbol(s)   Name of each exchange on which registered Common Stock, $0.01 par value per share   AWI   New York Stock Exchange Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter). Emerging growth company ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ◻           Section 8 – Other Events Item 8.01. Other Events On April 24, 2026, Armstrong World Industries, Inc. (the "Company") issued a press release announcing that its Board of Directors has declared a quarterly cash dividend of $0.339 per share of outstanding common stock payable on May 26, 2026 to stockholders of record as of the close of business on May 11, 2026. A copy of the press release is attached as Exhibit 99.1 hereto and incorporated herein by reference. Section 9 – Financial Statements and Exhibits Item 9.01 Financial Statements and Exhibits. (d) Exhibits No. 99.1   No. 104 Press Release of Armstrong World Industries, Inc. dated April 24, 2026   Cover Page Interactive Data File (embedded within the Inline XBRL document)       2   SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. ARMSTRONG WORLD INDUSTRIES, INC.     By: /s/ Jessica M. Cicali   Jessica M. Cicali   SVP General Counsel, Chief Compliance Officer, Secretary Date: April 24, 2026   3