Business	12 Months Ended
Dec. 31, 2020
Business [Abstract]
Business	NOTE 1. BUSINESS Armstrong World Industries, Inc. (“AWI”) is a Pennsylvania corporation incorporated in 1891. When we refer to “AWI,” the “Company,” “we,” “our” and “us” in these notes, we are referring to AWI and its subsidiaries. Acquisitions In December 2020, we acquired all of the issued and outstanding equity of Arktura LLC (“Arktura”) and certain subsidiaries with operations in the United States and Argentina. Arktura is a designer and fabricator of metal and felt ceilings, walls, partitions and facades with one manufacturing facility based in Los Angeles, California. In August 2020, we acquired the business and assets of Moz Designs, Inc. (“Moz”), based in Oakland, California. Moz is a designer and fabricator of custom architectural metal ceilings, walls, dividers and column covers for interior and exterior applications with one manufacturing facility. In July 2020, we acquired all of the issued and outstanding capital stock of TURF Design, Inc. (“Turf”), with one manufacturing facility in Elgin, Illinois and a design center in Chicago, Illinois. Turf is a designer and manufacturer of acoustic felt ceilings and wall products. In November 2019, we acquired the business and assets of MRK Industries, Inc. (“MRK”), based in Libertyville, Illinois. MRK is a manufacturer of specialty metal ceiling, wall and exterior solutions with one manufacturing facility. In March 2019, we acquired the business and assets of Architectural Components Group, Inc. (“ACGI”), based in Marshfield, Missouri. ACGI is a manufacturer of custom wood ceilings and walls with one manufacturing facility. In August 2018, we acquired the business and assets of Steel Ceilings, Inc. (“Steel Ceilings”), based in Johnstown, Ohio. Steel Ceilings is a manufacturer of aluminum and stainless metal ceilings that include architectural, radiant and security solutions with one manufacturing facility. In May 2018, we acquired the business and assets of Plasterform, Inc. (“Plasterform”), based in Mississauga, Ontario, Canada. Plasterform is a manufacturer of architectural cast ceilings, walls, facades, columns and moldings with one manufacturing facility. The operations, assets and liabilities of these acquisitions are included in our Architectural Specialties segment. See Note 5 for further information on our recent acquisitions. Discontinued Operations On September 30, 2019, we completed the sale of certain subsidiaries comprising our businesses and operations in Europe, the Middle East and Africa (including Russia) (“EMEA”) and the Pacific Rim, including the corresponding businesses and operations conducted by Worthington Armstrong Venture (“WAVE”), our joint venture with Worthington Industries, Inc. (“Worthington”) in which AWI holds a 50% interest (collectively, the “Sale”), to Knauf International GmbH (“Knauf”). The purchase price of $330.0 million was previously paid by Knauf to us during 2018 and was subject to certain post-closing adjustments for cash and debt as provided in the Purchase Agreement dated as of November 17, 2017, by and between us and Knauf (the “Purchase Agreement”), including adjustments based on the economic impact of any required regulatory remedies and a working capital adjustment. During 2020, we remitted $25.9 million, respectively, to WAVE for their remaining portion of the proceeds from Knauf. Also during 2020, WAVE paid each of AWI and Worthington dividends of $13.0 million relating to these payments. During the third quarter of 2020, we remitted $6.4 million to Knauf for working capital and other adjustments. In January 2021, we finalized the post-closing adjustments to purchase price related to certain pension liabilities assumed by Knauf in the Sale. During the fourth quarter of 2020, we recorded a $12.0 million loss primarily related to this purchase price adjustment, which is reflected within accounts payable and accrued expenses as of December 31, 2020. In 2019, we entered into a Transition Services Agreement with Knauf for its benefit and the benefit of a buyer of certain businesses divested by Knauf, pursuant to which we provided certain transition technology, finance and information technology support services. The Transition Services Agreement expired in 2020. In connection with the closing of the Sale, we also entered into (i) a royalty-free intellectual property License Agreement with Knauf under which they, and the buyers of certain businesses divested by Knauf, license patents, trademarks and know-how from us for use in licensed territories in which the business was conducted prior to the Sale, and (ii) a Supply Agreement with Knauf under which the parties may continue to purchase certain products from each other following the closing of the Sale. WAVE also entered into similar agreements with Knauf for such purposes. The term of the granted licenses, with respect to each intellectual property right, extend until the expiration or abandonment of each such intellectual property right. The EMEA and Pacific Rim segment historical financial results through September 30, 2019 have been reflected in AWI’s Consolidated Statements of Operations and Comprehensive Income as discontinued operations for all periods presented, while the assets and liabilities of discontinued operations have been removed from AWI’s Consolidated Balance Sheet as of December 31, 2019. COVID-19 Considerations The COVID-19 outbreak has created significant volatility and economic disruption and the impact on our future consolidated results of operations is uncertain. The extent to which COVID-19 impacts our employees, operations, customers, suppliers and financial results depends on numerous evolving factors that we are not able to accurately predict, including: the duration and scope of the pandemic; government actions taken in response to the pandemic; the availability and distribution of vaccinations; the impact on construction activity; the effect on our customers demand for our ceiling and wall systems; our ability to manufacture and sell our products; and the ability of our customers to pay for our products. While many of our products support life sustaining activities and essential construction, we, and certain of our customers or suppliers, may be impacted by state actions, orders and policies regarding the COVID-19 pandemic, including temporary closures of non-life sustaining businesses, shelter-in-place orders, and travel, social distancing and quarantine policies, the implementation and enforcement of which vary by individual U.S. states and by individual countries in the Americas. We did not record any asset impairments, inventory charges or material bad debt reserves related to COVID-19 during 2020 but future events may require such charges, which could have a material adverse effect on our financial condition, liquidity or results of operations.

Business

12 Months Ended

Dec. 31, 2020

NOTE 1. BUSINESS

Armstrong World Industries, Inc. (“AWI”) is a Pennsylvania corporation incorporated in 1891. When we refer to “AWI,” the “Company,” “we,” “our” and “us” in these notes, we are referring to AWI and its subsidiaries.

Acquisitions

In December 2020, we acquired all of the issued and outstanding equity of Arktura LLC (“Arktura”) and certain subsidiaries with operations in the United States and Argentina. Arktura is a designer and fabricator of metal and felt ceilings, walls, partitions and facades with one manufacturing facility based in Los Angeles, California.

In August 2020, we acquired the business and assets of Moz Designs, Inc. (“Moz”), based in Oakland, California. Moz is a designer and fabricator of custom architectural metal ceilings, walls, dividers and column covers for interior and exterior applications with one manufacturing facility.

In July 2020, we acquired all of the issued and outstanding capital stock of TURF Design, Inc. (“Turf”), with one manufacturing facility in Elgin, Illinois and a design center in Chicago, Illinois. Turf is a designer and manufacturer of acoustic felt ceilings and wall products.

In November 2019, we acquired the business and assets of MRK Industries, Inc. (“MRK”), based in Libertyville, Illinois. MRK is a manufacturer of specialty metal ceiling, wall and exterior solutions with one manufacturing facility.

In March 2019, we acquired the business and assets of Architectural Components Group, Inc. (“ACGI”), based in Marshfield, Missouri. ACGI is a manufacturer of custom wood ceilings and walls with one manufacturing facility.

In August 2018, we acquired the business and assets of Steel Ceilings, Inc. (“Steel Ceilings”), based in Johnstown, Ohio. Steel Ceilings is a manufacturer of aluminum and stainless metal ceilings that include architectural, radiant and security solutions with one manufacturing facility.

In May 2018, we acquired the business and assets of Plasterform, Inc. (“Plasterform”), based in Mississauga, Ontario, Canada. Plasterform is a manufacturer of architectural cast ceilings, walls, facades, columns and moldings with one manufacturing facility.

The operations, assets and liabilities of these acquisitions are included in our Architectural Specialties segment. See Note 5 for further information on our recent acquisitions.

Discontinued Operations

On September 30, 2019, we completed the sale of certain subsidiaries comprising our businesses and operations in Europe, the Middle East and Africa (including Russia) (“EMEA”) and the Pacific Rim, including the corresponding businesses and operations conducted by Worthington Armstrong Venture (“WAVE”), our joint venture with Worthington Industries, Inc. (“Worthington”) in which AWI holds a 50% interest (collectively, the “Sale”), to Knauf International GmbH (“Knauf”). The purchase price of $330.0 million was previously paid by Knauf to us during 2018 and was subject to certain post-closing adjustments for cash and debt as provided in the Purchase Agreement dated as of November 17, 2017, by and between us and Knauf (the “Purchase Agreement”), including adjustments based on the economic impact of any required regulatory remedies and a working capital adjustment. During 2020, we remitted $25.9 million, respectively, to WAVE for their remaining portion of the proceeds from Knauf. Also during 2020, WAVE paid each of AWI and Worthington dividends of $13.0 million relating to these payments. During the third quarter of 2020, we remitted $6.4 million to Knauf for working capital and other adjustments. In January 2021, we finalized the post-closing adjustments to purchase price related to certain pension liabilities assumed by Knauf in the Sale. During the fourth quarter of 2020, we recorded a $12.0 million loss primarily related to this purchase price adjustment, which is reflected within accounts payable and accrued expenses as of December 31, 2020.

In 2019, we entered into a Transition Services Agreement with Knauf for its benefit and the benefit of a buyer of certain businesses divested by Knauf, pursuant to which we provided certain transition technology, finance and information technology support services. The Transition Services Agreement expired in 2020. In connection with the closing of the Sale, we also entered into (i) a royalty-free intellectual property License Agreement with Knauf under which they, and the buyers of certain businesses divested by Knauf, license patents, trademarks and know-how from us for use in licensed territories in which the business was conducted prior to the Sale, and (ii) a Supply Agreement with Knauf under which the parties may continue to purchase certain products from each other following the

closing of the Sale. WAVE also entered into similar agreements with Knauf for such purposes. The term of the granted licenses, with respect to each intellectual property right, extend until the expiration or abandonment of each such intellectual property right.

The EMEA and Pacific Rim segment historical financial results through September 30, 2019 have been reflected in AWI’s Consolidated Statements of Operations and Comprehensive Income as discontinued operations for all periods presented, while the assets and liabilities of discontinued operations have been removed from AWI’s Consolidated Balance Sheet as of December 31, 2019.

COVID-19 Considerations

The COVID-19 outbreak has created significant volatility and economic disruption and the impact on our future consolidated results of operations is uncertain. The extent to which COVID-19 impacts our employees, operations, customers, suppliers and financial results depends on numerous evolving factors that we are not able to accurately predict, including: the duration and scope of the pandemic; government actions taken in response to the pandemic; the availability and distribution of vaccinations; the impact on construction activity; the effect on our customers demand for our ceiling and wall systems; our ability to manufacture and sell our products; and the ability of our customers to pay for our products. While many of our products support life sustaining activities and essential construction, we, and certain of our customers or suppliers, may be impacted by state actions, orders and policies regarding the COVID-19 pandemic, including temporary closures of non-life sustaining businesses, shelter-in-place orders, and travel, social distancing and quarantine policies, the implementation and enforcement of which vary by individual U.S. states and by individual countries in the Americas. We did not record any asset impairments, inventory charges or material bad debt reserves related to COVID-19 during 2020 but future events may require such charges, which could have a material adverse effect on our financial condition, liquidity or results of operations.