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                              October 26, 2022

       Christopher P. Calzaretta.
       Chief Financial Officer
       Armstrong World Industries, Inc.
       2500 Columbia Avenue
       Lancaster, Pennsylvania 17603

                                                        Re: Armstrong World
Industries, Inc.
                                                            Form 10-K for the
Fiscal Year Ended December 31, 2021
                                                            Filed February 22,
2022
                                                            Form 8-K
                                                            Furnished February
22, 2022
                                                            File No. 001-02116

       Dear Christopher P. Calzaretta.:

              We have limited our review of your filing to the financial
statements and related
       disclosures and have the following comments. In some of our comments, we
may ask you to
       provide us with information so we may better understand your disclosure.

              Please respond to these comments within ten business days by
providing the requested
       information or advise us as soon as possible when you will respond. If
you do not believe our
       comments apply to your facts and circumstances, please tell us why in
your response.

                                                        After reviewing your
response to these comments, we may have additional comments.

       Form 8-K furnished February 22, 2022

       Exhibit 99.1, page 7

   1.                                                   We note on page 9 that
the non-GAAP measure, adjusted free cash flow, is reconciled to
                                                        net cash provided by
operating and investing activities. Please advise how you considered
                                                        Question 102.07 of the
Compliance & Disclosure Interpretations for Non-GAAP Financial
                                                        Measures that states
"free cash flow" is typically calculated as cash flows from operating
                                                        activities presented in
the statement of cash flows under GAAP, less capital expenditures.

                                                        In addition, we note on
page 7 that disclosed adjusted free cash flow "provides insight into
                                                        the amount of cash that
the Company generates for discretionary uses, after expenditures
                                                        for capital investments
and adjustments for acquisitions and divestitures." Please tell us
                                                        how you considered
Question 102.07 of the Compliance & Disclosure Interpretations for
 Christopher P. Calzaretta.
Armstrong World Industries, Inc.
October 26, 2022
Page 2
         Non-GAAP Financial Measures that states "free cash flow" should not be
used in a
         manner that inappropriately implies that the measure represents the
residual cash flow
         available for discretionary expenditures.
Exhibit 99.1, page 8

2.       We note that the non-GAAP measure, adjusted EBITDA, is reconciled to
earnings (loss)
         from continuing operations, earnings (loss) before tax, and operating
income. Please
         reconcile adjusted EBITDA to net earnings (net income as presented in
the statement of
         operations under GAAP) in future filings. Refer to Question 103.02 of
the Compliance
         and Disclosure Interpretations for Non-GAAP Financial Measures. In
addition, please
         present this GAAP measure with greater or equal prominence to your
non-GAAP
         measure.
Investor presentation for Q2 2022 available from the Company's website, page 15

3.       We note the Company presented adjusted EBITDA in the investor
presentation. Please
         also present the most directly comparable GAAP measure in other public
disclosure, such
         as an investor presentation, in the future when a non-GAAP measure is
presented in
         accordance with Regulation G.
Form 10-K for the fiscal year ended December 31, 2022
Item 8. Financial Statements and Supplementary Data
Note 4. Revenue, page 49

4.       We note your disclosure of net sales by geographic area on page 48 and
net sales by major
         customer group for each segment on page 49. Please disclose revenues
from external
         customers for each product and service or each group of similar
products and services as
         required by ASC 280-10-50-40 or tell us and disclose why it is
impracticable to do so.
       In closing, we remind you that the company and its management are
responsible for the
accuracy and adequacy of their disclosures, notwithstanding any review,
comments, action or
absence of action by the staff.

       You may contact Stephany Yang at (202) 551-3167 or Kevin Woody at (202)
551-3629
with any questions.



FirstName LastNameChristopher P. Calzaretta.                  Sincerely,
Comapany NameArmstrong World Industries, Inc.
                                                              Division of
Corporation Finance
October 26, 2022 Page 2                                       Office of
Manufacturing
FirstName LastName