March 25, 2020

Brian L. MacNeal
Chief Financial Officer
Armstrong World Industries, Inc.
2500 Columbia Avenue
Lancaster, Pennsylvania 17603

       Re: Armstrong World Industries, Inc.
           Form 10-K for the Year Ended December 31, 2019
           Filed February 25, 2020
           File No. 001-02116

Dear Mr. MacNeal:

       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 10-K for the Year Ended December 31, 2019

Financial Statements
Notes to Consolidated Financial Statements
Note 2. Summary of Significant Accounting Policies
Revision of Previously Issued Financial Statements, page 44

1.    We note that you corrected an error related to the year ended December
31, 2017 you
      believed to be immaterial in the current December 31, 2019 10-K. As the
quantitative
      disclosures on page 44 indicate that the change increased your net loss
in 2017 by over
      50%, it is unclear why you believe such error to be immaterial. Please
provide us with
      your full materiality analysis and tell us your consideration of amending
your December
      31, 2017 10-K as well as filing an Item 4.02 8-K that such financial
statements should no
      longer be relied upon. We may have further comment after review of your
response.
 Brian L. MacNeal
Armstrong World Industries, Inc.
March 25, 2020
Page 2
Revenue Recognition, page 46

2.       We note from page seven that as part of the sale of your EMEA
businesses to Knauf, you
         entered into license agreements for the license of intellectual
property. To the extent
         material, please tell us the material terms of this agreement and your
consideration of
         disclosing how you account for such licensing agreements.
       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 Heather Clark at 202-551-3624 or Melissa Raminpour at
202-551-3379
with any questions.



FirstName LastNameBrian L. MacNeal                          Sincerely,
Comapany NameArmstrong World Industries, Inc.
                                                            Division of
Corporation Finance
March 25, 2020 Page 2                                       Office of
Manufacturing
FirstName LastName