X0306 4 2018-07-13 0 0000007431 ARMSTRONG WORLD INDUSTRIES INC AWI 0001310679 Spivy Gregory P ONE LETTERMAN DRIVE BUILDING D, 4TH FLOOR SAN FRANCISCO CA 94129 1 0 1 1 See Remarks 0001418814 ValueAct Holdings, L.P. ONE LETTERMAN DRIVE BUILDING D, 4TH FLOOR SAN FRANCISCO CA 94129 1 0 1 1 See Remarks 0001464912 ValueAct Capital Master Fund, L.P. ONE LETTERMAN DRIVE BUILDING D, 4TH FLOOR SAN FRANCISCO CA 94129 1 0 1 1 See Remarks 0001418812 VA Partners I, LLC ONE LETTERMAN DRIVE BUILDING D, 4TH FLOOR SAN FRANCISCO CA 94129 1 0 1 1 See Remarks 0001351069 ValueAct Capital Management, L.P. ONE LETTERMAN DRIVE BUILDING D, 4TH FLOOR SAN FRANCISCO CA 94129 1 0 1 1 See Remarks 0001351073 ValueAct Capital Management, LLC ONE LETTERMAN DRIVE BUILDING D, 4TH FLOOR SAN FRANCISCO CA 94129 1 0 1 1 See Remarks 0001418813 ValueAct Holdings GP, LLC ONE LETTERMAN DRIVE BUILDING D, 4TH FLOOR SAN FRANCISCO CA 94129 1 0 1 1 See Remarks Common Stock 2018-07-13 4 A 0 1558 0 A 7295 D Common Stock 6852612 I See Footnotes Restricted stock units granted under the 2016 Directors Stock Unit Plan, as amended, and as part of the Issuer's nonemployee Director Compensation Program. The units vest (contingent upon the Director's continued service as of such date) on the earlier of (i) the one-year anniversary of the grant; (ii) the death or total and permanent disability of the Director; or (iii) the date of any Change in Control Event (as defined in the Plan). Vested units will be acquirable by the Director, at the election of the Director: (i) at the vesting of the units at the one-year anniversary of the grant or (ii) at the time of the Director's termination of service. Represents an annual grant of restricted stock units as the equity portion of the Directors retainer for Board service under the Issuer's nonemployee Director Compensation Program. The grant date fair value of the units is calculated under the Financial Accounting Standards Board's Accounting Standards Codification Topic 718 using the closing stock price of the Issuer's common shares on July 13, 2018, the first business day following the Issuer's Annual Meeting of Shareholders, which price was $67.40. Includes vested and unvested units as well as units not yet acquirable by the Director. Under the terms of the 2008 Directors Stock Unit Plan, as amended (the "2008 Plan"), vested units under the 2008 Plan are not acquirable by the Director until (i) for those restricted stock units granted prior to June 2011, six (6) months following the termination of service on the Issuer's Board of Directors, and, (ii) for those units granted during and after June 2011, at the time of termination of service on the Issuer's Board of Directors. Under the terms of the 2016 Directors Stock Unit Plan, as amended (the "2016 Plan"), vested units under the 2016 Plan are not acquirable by the Director until, at the election of the Director: (i) the vesting of the units at the one-year anniversary of the grant or (ii) the time of the Director's termination of service. The ValueAct entities referred to in this footnote 4 are collectively referred to herein as "ValueAct Capital." Under an agreement with ValueAct Capital, Gregory P. Spivy is deemed to hold the common stock for the benefit of the limited partners of ValueAct Capital Master Fund, L.P. and indirectly for (i) VA Partners I, LLC as General Partner of ValueAct Capital Master Fund, L.P., (ii) ValueAct Capital Management, L.P. as the manager of ValueAct Capital Master Fund, L.P., (iii) ValueAct Capital Management, LLC as General Partner of ValueAct Capital Management, L.P., (iv) ValueAct Holdings, L.P. as the sole owner of the limited partnership interests of ValueAct Capital Management, L.P. and the membership interests of ValueAct Capital Management, LLC and as the majority owner of the membership interests of VA Partners I, LLC and (v) ValueAct Holdings GP, LLC as General Partner of ValueAct Holdings, L.P. Each reporting person listed herein disclaims beneficial ownership of the reported securities except to the extent of its pecuniary interest therein, and this report shall not be deemed an admission that such person is the beneficial owner of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose. The securities reported herein are directly beneficially owned by ValueAct Capital Master Fund, L.P. and may be deemed to be indirectly beneficially owned by (i) VA Partners I, LLC as General Partner of ValueAct Capital Master Fund, L.P., (ii) ValueAct Capital Management, L.P. as the manager of ValueAct Capital Master Fund, L.P., (iii) ValueAct Capital Management, LLC as General Partner of ValueAct Capital Management, L.P., (iv) ValueAct Holdings, L.P. as the sole owner of the limited partnership interests of ValueAct Capital Management, L.P. and the membership interests of ValueAct Capital Management, LLC and as the majority owner of the membership interests of VA Partners I, LLC and (v) ValueAct Holdings GP, LLC as General Partner of ValueAct Holdings, L.P. - The reporting persons herein may be deemed to be members of a "group" for purposes of the Securities Exchange Act of 1934, as amended. Each reporting person disclaims beneficial ownership of any securities deemed to be owned by the group that are not directly owned by such reporting person. This report shall not be deemed an admission that such reporting person is a member of a group or the beneficial owner of any securities not directly owned by such reporting person. - Gregory P. Spivy, a Partner at ValueAct Capital, serves on the board of directors of the Issuer. As a result, the other reporting persons herein may be deemed directors by deputization. /s/ Gregory P. Spivy 2018-07-17 VALUEACT HOLDINGS, L.P., By: VALUEACT HOLDINGS GP, LLC, its General Partner, By: /s/ Bradley E. Singer, Chief Operating Officer 2018-07-17 VALUEACT CAPITAL MASTER FUND, L.P., By: VA PARTNERS I, LLC, its General Partner, By: /s/ Bradley E. Singer, Chief Operating Officer 2018-07-17 VA PARTNERS I, LLC, By: /s/ Bradley E. Singer, Chief Operating Officer 2018-07-17 VALUEACT CAPITAL MANAGEMENT, L.P., By: VALUEACT CAPITAL MANAGEMENT, LLC, its General Partner, By: /s/ Bradley E. Singer, Chief Operating Officer 2018-07-17 VALUEACT CAPITAL MANAGEMENT, LLC, By: /s/ Bradley E. Singer, Chief Operating Officer 2018-07-17 VALUEACT HOLDINGS GP, LLC, By: /s/ Bradley E. Singer, Chief Operating Officer 2018-07-17