Execution Version 1011705623v1 COOPERATION AGREEMENT This Cooperation Agreement (this “Agreement”), dated as of November 20, 2025 (the “Effective Date”), is by and among Irenic Capital Management LP, a Delaware limited partnership (“Irenic”), Irenic Capital Management GP LLC, a Delaware limited liability company, Irenic Capital Evergreen Master Fund LP, a Cayman Islands limited partnership and Irenic Capital Evergreen Fund GP LLC, a Delaware limited liability company (each, an “Irenic Party,” and, together, the “Irenic Parties”), and Atkore Inc., a Delaware corporation (the “Company”). WHEREAS, the Company and the Irenic Parties have engaged in discussions concerning the Company; and WHEREAS, the Company and the Irenic Parties desire to enter into an agreement regarding the appointment of one (1) new director to the Board of Directors of the Company (the “Board”) and certain other matters, in each case, on the terms and subject to the conditions set forth herein; NOW, THEREFORE, in consideration of and reliance upon the mutual covenants and agreements contained herein, the receipt and sufficiency of which are hereby acknowledged, the Irenic Parties and the Company agree as follows: Section 1. Board of Directors. (a) New Independent Director. Within two (2) Business Days following the Company’s receipt of the Irenic Parties’ nomination letter authorizing the appointment of Franklin S. Edmonds, Jr. to the Board (the “Notice Date”), the Board and all applicable committees thereof shall take (or shall have taken) such actions as are necessary in accordance with the Company’s Fourth Amended and Restated Bylaws, effective November 13, 2023 (the “Bylaws”), and the Delaware General Corporation Law (the “DGCL”) to increase the size of the Board by one (1) director and to appoint Franklin S. Edmonds, Jr. to the Board (the “New Director”), to fill the vacancy created by such increase in the Board, with an initial term expiring at the Company’s 2026 Annual Meeting of Stockholders (the “2026 Annual Meeting”). (b) New Director Agreements, Arrangements, and Understandings. Each of the Irenic Parties represents, warrants, and agrees that, except as disclosed in writing to the Company prior to the date hereof, neither it nor any of its Affiliates (i) has paid or will pay any compensation to the New Director or any other member of the Board or any officer or consultant to the Board or any committee thereof in connection with such individual’s nomination to or service on or to the Board or any committee thereof or (ii) has or will have any agreement, arrangement or understanding (whether compensatory or otherwise), written, or oral, with the New Director or the Consultant (as defined below) in connection with such individual’s nomination to or service on the Board or any committee thereof or the Company’s performance or stock price. (c) 2026 Annual Meeting Nominees. The Company and all applicable committees thereof shall take such actions as are necessary so that the slate of nominees recommended by the Board in the Company’s proxy statement and on its proxy card relating to the 2026 Annual

2 1011705623v1 Meeting shall include the New Director and nine (9) other nominees selected by the Board to stand for election at the 2026 Annual Meeting. (d) Replacement Director. If the New Director is unable or unwilling to serve as a director, resigns as a director, is removed as a director, or ceases to be a director for any other reason prior to the expiration of the Cooperation Period, and the Irenic Parties beneficially hold a Net Long Position equal to, or have aggregate net long economic exposure equal to, at least 1.5% of the then outstanding Common Stock (the “Minimum Ownership Threshold”), the Company and the Irenic Parties shall cooperate in good faith to identify and mutually agree, subject to Sections 1(e) and 1(g), upon a substitute director who meets the requirements of a Qualified Director (such individual, the “Replacement Director”), and the Board shall take such actions as are necessary to appoint such Replacement Director to serve as a director of the Company for the remainder of the New Director’s term. Effective upon the appointment of the Replacement Director to the Board, such Replacement Director will be considered the New Director for all purposes of this Agreement. In the event the Irenic Parties seek to exercise their rights pursuant to this Section 1(d), the Irenic Parties shall certify in writing to the Company that the Minimum Ownership Threshold is satisfied as of the time of such exercise. (e) Company Policies. The parties acknowledge that any New Director, upon election or appointment to the Board, will be governed by the same protections and obligations regarding confidentiality, conflicts of interest, related person transactions, fiduciary duties, codes of conduct, trading, and disclosure policies, director resignation policy, share ownership guidelines, and other governance guidelines and policies of the Company as other directors of the Company (collectively, “Company Policies”), and, except as may be subsequently waived by the Irenic Parties in writing, shall have the same rights and benefits, including with respect to insurance, indemnification, compensation, and fees, as are applicable to all directors of the Company. The Company represents and warrants that, (i) no Company Policy shall be violated by any New Director receiving indemnification and/or reimbursement of expenses from the Irenic Parties or their respective Affiliates, provided that any New Director neither accepts nor receives compensation from the Irenic Parties or their respective Affiliates with respect to any New Director’s service or action as a director of the Company, (ii) the Company Policies do not apply to the Irenic Parties and their Affiliates (excluding for the avoidance of doubt any New Director and the Consultant, as defined below) as a result of any New Director’s appointment to, or service on, the Board, including Company Policies with respect to trading in the Company’s securities, as they are not directors or employees of the Company (for the avoidance of doubt, the Irenic Parties are aware of the federal securities laws relating to trading while in possession of material, non-public information) and (iii) prior to the termination of the Cooperation Period, any changes to the Company Policies, or new Company Policies, will be adopted in good faith and not for the purpose of undermining or conflicting with the arrangements contemplated hereby. (f) 2026 Annual Meeting. The Company shall use its best efforts to hold the 2026 Annual Meeting no later than February 27, 2026, subject to any delay necessitated by compliance with applicable law or regulatory or judicial or stock exchange order, published interpretation or requirement.

3 1011705623v1 (g) Strategic Review Committee. (i) Within two (2) Business Days following the Notice Date, the Board and all applicable committees thereof shall take (or shall have taken) such actions as are necessary in accordance with Section 141(c) of the DGCL and the Bylaws to establish a committee of the Board (the “Strategic Review Committee”) to oversee, evaluate and provide advice to the Board regarding its review of strategic alternatives. (ii) Effective upon the New Director’s appointment to the Board, and once the Strategic Review Committee has been formed, the Board and all applicable committees thereof shall take all necessary actions to appoint the New Director to the Strategic Review Committee. In accordance with the immediately preceding sentence, the Board and the Strategic Review Committee shall take all necessary actions to maintain the New Director as a member of the Strategic Review Committee until the end of the Cooperation Period. During the Cooperation Period, (A) the Strategic Review Committee shall be composed of no more than five (5) members and (B) any subcommittee of the Strategic Review Committee shall include the New Director. (h) Strategic Review Process. (i) Within seven (7) Business Days following the establishment of the Strategic Review Committee, the Company represents, warrants, and agrees that, it shall commence a process to hire a nationally recognized and independent investment bank or, in the event the Company has already hired a nationally recognized and independent investment bank, engage with such investment bank (the “Investment Bank”) to oversee, evaluate and conduct a process to review the Company’s strategic alternatives (the “Review Process”), which process shall include, among other things, soliciting proposals for a merger or other business combination involving the Company or any other direct or indirect sale or other disposition of substantially all of the capital stock of the Company or substantially all of the business or assets of the Company (a “Company Sale Transaction"). (ii) The Company hereby agrees that the Irenic Parties and their Representatives shall be afforded reasonable opportunities, upon reasonable advance notice to the Chair of the Strategic Review Committee, to provide comments to and engage in discussions with, each of the Strategic Review Committee and the Investment Bank; provided that (i) such engagement and discussions do not unreasonably interfere with the ordinary course operations of either the Strategic Review Committee or the Investment Bank and (ii) the Investment Bank and the Strategic Review Committee shall not disclose to the Irenic Parties any material non-public information relating to the Company or the Review Process without the prior written consent of the Irenic Parties. (i) Special Advisor. Within two (2) Business Days following the Notice Date, the Company and Bruce M. Taten (the “Consultant”) shall execute a consulting agreement (the “Consulting Agreement”) in substantially the form attached hereto as Exhibit A. Pursuant to the Consulting Agreement, the Consultant will serve as a special advisor to the Strategic Review Committee. In addition to, and not in limitation of, the termination rights set forth in Section

4 1011705623v1 1(j), the Company’s obligations under this Section 1(i) shall terminate upon any material breach of the Consulting Agreement by the Consultant as determined by a court of competent jurisdiction, upon five (5) Business Days’ written notice by the Company to the Consultant and the Irenic Parties if such breach has not been cured within such notice period. (j) Termination. The Company’s obligations under this Section 1 shall terminate upon the earliest of: (i) any material breach of this Agreement (including Section 2) by any Irenic Party or any other Restricted Person (as defined below) as determined by a court of competent jurisdiction, upon five (5) Business Days’ written notice by the Company to the Irenic Parties if such breach has not been cured within such notice period; provided that the Company is not in material breach of this Agreement at the time such notice is given or prior to the end of the notice period, (ii) such time as the New Director notifies the Company of his or her intent to resign from the Board and the Irenic Parties waive in writing any right to have a Replacement Director appointed or (iii) the Irenic Parties or any other Restricted Person submits any director nomination for election at any meeting of the Company’s stockholders. Upon the occurrence of an event described in any of clause (i) or (iii) of this Section 1(j), any New Director shall promptly offer to resign from the Board (and, if requested by the Company, promptly deliver his or her written resignation to the Board for his or her immediate resignation, it being understood that it shall be in the Board’s sole discretion whether to accept or reject such resignation). The Irenic Parties agree to cause, and agree to cause their respective Affiliates to cause, any New Director (or a Replacement Director) to resign from the Board if he or she fails to resign if and when requested pursuant to this Section 1(j). Section 2. Cooperation. (a) Board Refreshment. On or prior to May 20, 2026, the Board and all applicable committees thereof, shall take (or shall have taken) such actions as are necessary in accordance with the Bylaws and the DGLC to (i) increase the size of the Board by one (1) director and (ii) appoint a candidate who meets the requirements of a Qualified Director to serve on the Board as an additional director, who has been mutually agreed upon by the Board and the Irenic Parties. Prior to such appointment, the Irenic Parties shall certify in writing to the Company that the Minimum Ownership Threshold is satisfied. Any candidate appointed to the Board pursuant to this Section 2(a) shall be deemed a New Director for all purposes of this Agreement, except for Section 1(c) and Section 1(g)(ii). (b) Non-Disparagement. During the Cooperation Period, the Company and each Irenic Party shall refrain from making, and shall cause their respective Controlling and Controlled (and under common Control) Affiliates and Representatives (solely in the context of their representation of such party) and (i) in the case of each Irenic Party, each of its and their respective principals, directors, members, managers, general partners, officers and employees (collectively, the “Irenic Covered Persons”), and (ii) in the case of the Company, its directors, officers and members of the Executive Leadership Team (the “Company Covered Persons”) not to make or cause to be made any public written or oral statement or announcement (including any statement or announcement that can reasonably be expected to become public or require public disclosure) (each, a “Statement”) that constitutes an ad hominem attack on, that otherwise disparages, defames, impugns (whether publicly or privately) or publicly criticizes, or that is reasonably likely to damage the reputation of (A) in the case of any Statement by any of the

5 1011705623v1 Irenic Parties or the Irenic Covered Persons: the Company, any of its Affiliates or any of its or their respective current or former directors, officers or employees; and (B) in the case of any Statement by the Company or the Company Covered Persons: any of the Irenic Parties, any of their respective Affiliates or any of their respective current or former Irenic Covered Persons, in each case including (x) in any Statement, document, or report filed with, furnished to, or otherwise provided to the SEC or any other governmental or regulatory authority, (y) in any press release or other form of Statement made available to any form of media, and (z) to any journalist or member of the media (including in a television, radio, newspaper, or magazine interview, podcast or Internet or social media communication). The foregoing shall not (1) restrict the ability of any Person to comply with any subpoena or other legal or regulatory process or respond to a request for information from any governmental or regulatory authority with jurisdiction over such Person or to enforce such Person’s rights under this Agreement or (2) apply to any private communications among the Irenic Parties and their Affiliates, the Irenic Covered Persons and their Representatives (in their respective capacities as such), on the one hand, and among the Company and its Affiliates, the Company Covered Persons and Representatives (in their respective capacities as such), on the other hand. (c) Voting. During the Cooperation Period, each Irenic Party will cause all of the Common Stock that such Irenic Party or any of its Controlling or Controlled Affiliates has the right to vote (or to direct the vote), directly or indirectly, as of the applicable record date, to be present in person or by proxy for quorum purposes and to be voted at any meeting of stockholders of the Company or at any adjournment or postponement thereof or to deliver any consent or consent revocation, as applicable, in connection with any action by written consent of the stockholders of the Company in lieu of a meeting, (i) in favor of each director nominated and recommended by the Board for election at any meeting of stockholders of the Company or action by written consent of stockholders of the Company held during the Cooperation Period, (ii) against any nominees for director that are not approved and recommended by the Board for election at any such meeting or through any such written consent, (iii) against any proposal or resolution to remove any member of the Board, and (iv) in accordance with the recommendations by the Board on all other proposals or business that may be the subject of stockholder action at such meetings or pursuant to written consents; provided, however, that the Irenic Parties and their Affiliates shall be permitted to vote in their sole discretion on any proposal with respect to any Extraordinary Transaction (as defined below); provided, further, that, in the event that both Institutional Shareholder Services and Glass Lewis & Co. (including any successor thereof) issue a voting recommendation that differs from the voting recommendation of the Board with respect to any Company-sponsored proposal submitted to stockholders at a stockholder meeting (other than with respect to the election of directors to the Board, the removal of directors from the Board, the size of the Board or the filling of any vacancy on the Board), the Irenic Parties and their Affiliates shall be permitted to vote in their sole discretion with respect to such proposal. (d) Standstill. During the Cooperation Period, each Irenic Party will not, and will cause its Controlling and Controlled Affiliates (and those under common Control) and its and their respective Representatives acting on their behalf (collectively with the Irenic Parties, the “Restricted Persons”) to not, directly or indirectly, without the prior written consent, invitation, or authorization of the Board:

6 1011705623v1 (i) acquire, or offer or agree to acquire, by purchase or otherwise, or direct or act in concert with any Third Party in the acquisition of record or beneficial ownership of or economic exposure to any securities of the Company or rights or options to acquire any securities of the Company, or engage in any swap or hedging transaction, or other derivative agreement of any nature with respect to any securities of the Company, in each case, if such acquisition, offer, agreement or transaction would result in the Irenic Parties, together with their Affiliates, having beneficial ownership of more than 4.99%, or aggregate economic exposure to more than 9.99%, of the shares of Common Stock outstanding at such time; (ii) alone or in concert with any one or more Third Parties, (A) call or seek to call (either publicly or privately) a meeting of the Company’s stockholders or act by written consent in lieu of a meeting (or call or seek to call for the setting of a record date therefor), (B) seek election or appointment to, or representation on, the Board or nominate or propose the nomination of, or recommend the nomination of, any candidate to the Board, except as expressly set forth in Section 1, (C) make or be the proponent of any stockholder proposal to the Company, the Board or any of its committees, (D) seek (including through any “withhold” or similar campaign) the removal of any member of the Board, or (E) conduct, call for or publicly support a referendum of stockholders of the Company; provided that nothing in this Agreement will prevent the Irenic Parties or their Affiliates from taking actions in furtherance of privately identifying any Replacement Director in accordance with Section 1(d) following the departure of a New Director, identifying a candidate to serve as a Qualified Director pursuant to Section 2(a) or in anticipation of the potential imminent departure of a New Director (it being understood that prior to taking such action, the Irenic Parties will first notify the Company of such potential imminent departure), as applicable; (iii) make any request for stockholder list materials or other books and records of the Company or any of its Affiliates, whether pursuant to Section 220 of the DGCL or under any statutory or regulatory provision relating to stockholder access to books or records of the Company or any of its Affiliates; (iv) engage in any “solicitation” (as such term is used in the proxy rules of the SEC, but including, notwithstanding anything to the contrary in Rule 14a-2 under the Exchange Act, solicitations of ten (10) or fewer shareholders that would otherwise be excluded from the definition of “solicitation” pursuant to Rule 14a-2(b)(2) under the Exchange Act) of one or more proxies or consents with respect to the election or removal of one or more directors of the Company or any other matter or proposal relating to the Company or become a “participant” (as such term is defined in Instruction 3 to Item 4 of Schedule 14A under the Exchange Act) in any such solicitation of proxies or consents; (v) seek to effect, make or submit any proposal, or offer for (with or without one or more conditions), either alone or in concert with others, or publicly announce any intention to effect or cause or participate or in any way assist, facilitate or encourage any other person to effect or seek to effect, offer for, or make or submit any proposal any tender offer, exchange offer, merger, consolidation, amalgamation, acquisition of any securities (or beneficial ownership thereof) or rights or options to acquire any securities

7 1011705623v1 (or beneficial ownership thereof), acquisition of any assets, indebtedness or businesses, sale of all or substantially all assets, spinoff, splitoff or other similar separation of one or more business units, separation, business combination, recapitalization, restructuring, reorganization, liquidation, dissolution or other extraordinary transaction involving the Company or any of its direct or indirect subsidiaries and joint ventures or any of their respective securities or assets) (each, an “Extraordinary Transaction”); provided that the foregoing shall not preclude: (x) the Irenic Parties from acquiring any rights or options to acquire any securities (or beneficial ownership thereof) of the Company to the extent not prohibited by Section 2(d)(i), (y) the Irenic Parties from participating in an Extraordinary Transaction on the same basis as other stockholders of the Company, or (z) following such time as the Company has signed a definitive agreement with respect to any such Extraordinary Transaction, seeking to participate with the counterparty to such Extraordinary Transaction; (vi) make any proposal with respect to (A) any change in the number or identity of directors of the Company or the filling of any vacancy on the Board, other than as provided under Section 1 of this Agreement, (B) any change in the capitalization, capital allocation policy or dividend policy of the Company, (C) any other change in the Company’s management or corporate or governance structure, (D) any waiver, amendment or modification to the Company’s Certificate of Incorporation or the Bylaws (collectively, the “Organizational Documents”), (E) causing a class of securities of the Company to be delisted from, or to cease to be authorized to be quoted on, any securities exchange, or (F) causing a class of securities of the Company to become eligible for termination of registration pursuant to Section 12(g)(4) of the Exchange Act; (vii) knowingly encourage or advise any Third Party or knowingly assist any Third Party in encouraging or advising any other Person (A) with respect to the giving or withholding of any proxy or consent relating to, or other authority to vote, any securities of the Company or any securities convertible or exchangeable into or exercisable for any such securities, or (B) in conducting any type of referendum relating to the Company (including for the avoidance of doubt with respect to the Company’s management or the Board), other than such encouragement or advice that is consistent with the Board’s recommendation in connection with such matter, or as otherwise expressly permitted by this Agreement; (viii) form, join, knowingly encourage or knowingly participate in or act in concert with any Group with respect to any of its securities of the Company, or any securities convertible or exchangeable into or exercisable for any such securities, other than solely with Affiliates of the Irenic Parties with respect to securities of the Company now or hereafter owned by them; (ix) enter into any voting trust, arrangement or agreement with respect to any securities of the Company, or any securities convertible or exchangeable into or exercisable for any such securities, or subject any securities of the Company, or any securities convertible or exchangeable into or exercisable for any such securities, to any voting trust, arrangement or agreement (excluding customary brokerage accounts, margin accounts, prime brokerage accounts and the like), in each case other than (A) this

8 1011705623v1 Agreement, (B) solely between or among any two or more of the Irenic Parties and their Affiliates, or (C) granting any proxy in any solicitation approved by the Board and consistent with Section 2(c) above; (x) engage in any short sale or any purchase, sale, or grant of any option, warrant, convertible security, stock appreciation right, or other similar right (including any put or call option or “swap” transaction) with respect to any security (other than any index fund, exchange-traded fund, benchmark fund or broad basket of securities) that includes, relates to, or derives any significant part of its value from a decline in the market price or value of any of the Company’s securities or would, individually or in the aggregate, result in the Irenic Parties ceasing to have a Net Long Position in the Company; (xi) sell, offer or agree to sell, directly or indirectly, through swap or hedging transactions or otherwise, all or substantially all, voting rights decoupled from the underlying Common Stock held by a Restricted Person to any Third Party; (xii) institute, solicit or join as a party any litigation, arbitration or other proceeding against or involving the Company, any of its subsidiaries or any of its or their respective current or former directors or officers (including derivative actions in the name of the Company); provided, however, that for the avoidance of doubt, the foregoing shall not prevent any Irenic Party from (A) bringing litigation against the Company to enforce any express provision of this Agreement instituted in accordance with and subject to Section 10, (B) making any counterclaim with respect to any proceeding initiated by, or on behalf of, the Company or its Affiliates against any Irenic Party, (C) bringing bona fide commercial disputes that do not relate to the subject matter of this Agreement, (D) exercising statutory appraisal rights, or (E) responding to or complying with validly issued legal process; (xiii) take any action that would or would reasonably be expected to require the Company to make a public announcement regarding any of the types of matters set forth in this Section 2(d); (xiv) enter into any negotiation, agreement, arrangement, or understanding (whether written or oral) with any Third Party to take any action that the Restricted Persons are prohibited from taking pursuant to this Section 2(d); or (xv) make any request or submit any proposal to amend or waive any of the terms of this Agreement (including this subclause), in each case publicly or that would reasonably be expected to result in a public announcement or disclosure of such request or proposal or give rise to a requirement to so publicly announce or disclose such request or proposal by the Company or any of the Restricted Persons; provided that the restrictions in this Section 2(d) shall terminate automatically upon the earliest of the following (A) upon (x) any failure (I) to appoint the New Director to the Board in accordance with Section 1(a) or to the Strategic Review Committee in accordance with Section 1(g), (II) to include the New Director (or if applicable any Replacement Director) in the slate of

9 1011705623v1 nominees recommended by the Board in the Company’s proxy statement and on its proxy card relating to the 2026 Annual Meeting in accordance with Section 1(c) or Section 1(d), (III) to issue the Press Release (as defined below) in accordance with Section 3, or (IV) to pay the expense reimbursement pursuant to Section 9, or (y) any other material breach of this Agreement by the Company as determined by a court of competent jurisdiction, in the case of either clause (x) or (y) upon five (5) Business Days’ written notice by any of the Irenic Parties to the Company if such breach has not been cured within such notice period; provided that the Irenic Parties are not in material breach of this Agreement at the time such notice is given or prior to the end of the notice period; (B) any material breach of the Consulting Agreement by the Company, as determined by a court of competent jurisdiction, upon five (5) Business Days’ written notice by any of the Irenic Parties or Mr. Taten to the Company if such breach has not been cured within such notice period; provided that Mr. Taten is not in material breach of the Consulting Agreement and the Irenic Parties are not in material breach of this Agreement at the time such notice is given or prior to the end of the notice period; (C) the Company’s entry into (x) a definitive agreement with respect to any Extraordinary Transaction that would result in the acquisition by any Person or Group of more than 50% of the Common Stock or assets having an aggregate value exceeding 50% of the aggregate enterprise value of the Company, (y) one or more definitive agreements providing for the acquisition by the Company or its subsidiaries of one or more businesses or assets having an aggregate value exceeding 25% of the aggregate enterprise value of the Company during the Cooperation Period, or (z) one or more definitive agreements providing for a transaction or series of related transactions which would in the aggregate result in the Company issuing to one or more Third Parties at least 20% of the Common Stock (including on an as-converted basis, and including other securities of the Company with comparable voting power) outstanding immediately prior to such issuance(s) (including in a PIPE, convertible note, convertible preferred security or similar structure) during the Cooperation Period (provided that securities issued as consideration for (or in connection with) the acquisition of the assets, securities and/or business(es) of another Person by the Company or one or more of its subsidiaries shall not be counted toward this clause (z)); and (D) the commencement of any tender or exchange offer (by any Person or Group other than the Irenic Parties or their Affiliates) which, if consummated, would constitute an Extraordinary Transaction that would result in the acquisition by any Person or Group of more than 50% of the Common Stock, where the Company files with the SEC a Schedule 14D-9 (or amendment thereto) that does not recommend that its stockholders reject such tender or exchange offer (it being understood that nothing herein will prevent the Company from issuing a “stop, look and listen” communication pursuant to Rule 14d-9(f) promulgated by the SEC under the Exchange Act in response to the commencement of any tender or exchange offer); provided that, in the event the restrictions in this Section 2(d) terminate pursuant to the foregoing clauses (C) or (D) of this Section 2(d) and any of the Irenic Parties determine to solicit proxies against any transactions contemplated by (C) and (D), any New Director shall deliver his or her written resignation to the Board for his or her immediate resignation prior to the commencement of any soliciting activities by the Irenic Parties; provided further that, notwithstanding the foregoing, in the event the Company has entered into a definitive written agreement for the consummation of an Extraordinary Transaction pursuant to the foregoing clauses (C) or (D), the restrictions set forth in Section 2(d)(v) shall not automatically terminate, but shall continue and remain in effect until the closing of such Extraordinary Transaction.

10 1011705623v1 Notwithstanding anything to the contrary in this Agreement, nothing in this Agreement (including the restrictions in this Section 2(d)) will prohibit or restrict any Restricted Person from (I) stating how it intends to vote with respect to an Extraordinary Transaction that is publicly disclosed by the Company, if any, and the reasons therefor, (II) making any factual statement to comply with any subpoena or other legal process or respond to a request for information from any governmental authority with jurisdiction over such Restricted Person (so long as such process or request did not arise as a result of any discretionary act by any Restricted Person); provided that such Restricted Person will notify the Company promptly in writing (if reasonably practicable and to the extent not legally prohibited) of the existence, terms, and circumstances surrounding such request or requirement; provided, further, that no Restricted Person shall be required to provide the notice to the Company referenced in the immediately preceding proviso in the case of disclosures required to be made by such Restricted Person in the course of a routine audit or review by a competent regulatory or administrative authority which is not specifically related to the Company or such Restricted Person’s interactions with the Company, (III) granting any lien or encumbrance on any claim or interest in favor of a bank or broker- dealer or prime broker holding such claim or interest in custody or prime brokerage in the ordinary course of business, which lien or encumbrance is released upon the transfer of such claim or interest in accordance with the terms of the custody or prime brokerage agreement(s), as applicable, (IV) negotiating, evaluating or trading, directly or indirectly, in any index fund, exchange-traded fund, benchmark fund or broad basket of securities that may contain or otherwise reflect the performance of, but does not primarily consist of, securities of the Company, or (V) providing its views privately to the Investment Bank, the Strategic Review Committee, any member of the Board or to the Company’s Chief Executive Officer, Chief Financial Officer, or General Counsel or any financial or legal advisors that have been identified by the Chief Executive Officer to the Irenic Parties regarding any matter, or privately requesting a waiver of any provision of this Agreement, as long as such private communications or requests would not reasonably be expected to require public disclosure of such communications or requests by the Company or any of the Restricted Persons. Section 3. Public Announcement. Unless otherwise agreed in writing by the Company and the Irenic Parties, not later than 6:00 p.m. Eastern Time on November 20, 2025, the Company and the Irenic Parties shall issue a press release (the “Press Release”), in the form of Exhibit B attached hereto. The Company shall file with the SEC a Current Report on Form 8-K (the “Form 8-K”) with respect to this Agreement and the Consulting Agreement. The Company shall provide the Irenic Parties with a copy of the Form 8-K prior to any issuance of or filing with the SEC and shall consider any reasonable and timely comments of the Irenic Parties and their Representatives. Except as required by law or the rules of any stock exchange, or expressly permitted by the terms of this Agreement, neither the Company or any of its Affiliates nor the Irenic Parties or any of their Affiliates shall make any public statement (or other communication reasonably expected to become or result in a public disclosure) regarding the subject matter of this Agreement, the Consulting Agreement or the matters set forth in the Press Release without the prior written consent of the other party (not to be unreasonably withheld, conditioned or delayed). Section 4. Representations and Warranties of the Company. The Company represents and warrants to the Irenic Parties that: (a) the Company has the power and authority to execute, deliver and carry out the terms and provisions of this Agreement and to consummate the

11 1011705623v1 transactions contemplated by this Agreement; (b) this Agreement has been duly and validly authorized, executed, and delivered by the Company, constitutes a valid and binding obligation and agreement of the Company and, assuming the valid execution and delivery hereof by each of the other parties, is enforceable against the Company in accordance with its terms, except as enforcement of this Agreement may be limited by applicable bankruptcy, insolvency, reorganization, moratorium, fraudulent conveyance, or similar laws generally affecting the rights of creditors and subject to general equity principles; and (c) the execution, delivery and performance of this Agreement by the Company does not and will not (i) violate or conflict with any law, rule, regulation, order, judgment or decree applicable to the Company, or (ii) result in any breach or violation of or constitute a default (or an event that, with notice or lapse of time or both, could constitute a breach, violation or default) under or pursuant to, result in the loss of a material benefit under, or give any right of termination, amendment, acceleration or cancellation of, any organizational document, agreement, contract, commitment, understanding or arrangement to which the Company is a party or by which it is bound. Section 5. Representations and Warranties of the Irenic Parties. Each Irenic Party represents and warrants to the Company that: (a) such Irenic Party has the power and authority to execute, deliver and carry out the terms and provisions of this Agreement and to consummate the transactions contemplated by this Agreement; (b) this Agreement has been duly and validly authorized, executed and delivered by such Irenic Party, constitutes a valid and binding obligation and agreement of such Irenic Party and, assuming the valid execution and delivery hereof by each of the other parties, is enforceable against such Irenic Party in accordance with its terms, except as enforcement of this Agreement may be limited by applicable bankruptcy, insolvency, reorganization, moratorium, fraudulent conveyance or similar laws generally affecting the rights of creditors and subject to general equity principles; (c) the execution, delivery and performance of this Agreement by such Irenic Party does not and will not (i) violate or conflict with any law, rule, regulation, order, judgment or decree applicable to such Irenic Party, or (ii) result in any breach or violation of or constitute a default (or an event that, with notice or lapse of time or both, could constitute a breach, violation or default) under or pursuant to, or result in the loss of a material benefit under, or give any right of termination, amendment, acceleration or cancellation of, any organizational document, agreement, contract, commitment, understanding or arrangement to which such Irenic Party is a party or by which it is bound; and (d) the Irenic Parties, together with their Affiliates, (i) beneficially own (as defined in Rule 13d-3 under the Exchange Act) in the aggregate 13,977 shares of Common Stock and (ii) have a Net Long Position in less than 3% of the shares of Common Stock, in each case, as of the date hereof. Section 6. Withdrawal of Nomination Notice; 2026 Annual Meeting. Concurrently with and effective upon the appointment of the New Director, the Irenic Parties shall irrevocably withdraw, and shall be deemed to have (automatically and without any further action by the Irenic Parties or any other person being required) irrevocably withdrawn, the notice of director nominations and bylaws proposal from the Irenic Parties dated October 28, 2025 (the “Nomination Notice”), and such Nomination Notice and the nominations and proposal set forth therein shall be deemed (automatically and without any further action by the Irenic Parties or any other person being required) null, void and without effect. The Irenic Parties hereby further agree that they shall immediately cease all efforts, direct or indirect, in furtherance of the Nomination Notice and any related solicitation in connection therewith, including any negative solicitation

12 1011705623v1 efforts relating to the 2026 Annual Meeting concerning the Company and members of the slate of nominees proposed by the Company. Section 7. Definitions. For purposes of this Agreement: (a) the term “Affiliate” has the meaning set forth in Rule 12b-2 under the Exchange Act and shall include any Person who otherwise qualifies as an Affiliate at any time subsequent to the date of this Agreement; provided that none of the Company or its Affiliates or Representatives, on the one hand, and the Irenic Parties and their Affiliates or Representatives, on the other hand, shall be deemed to be “Affiliates” with respect to the other for purposes of this Agreement; provided, further, that “Affiliates” of a Person shall not include any entity solely by reason of the fact that one or more of such Person’s employees or principals serves as a member of such entity’s board of directors or similar governing body, unless such Person otherwise Controls such entity; provided, further, that, with respect to the Irenic Parties, “Affiliates” shall not include any portfolio operating company (as such term is understood in the private equity industry) of any of the Irenic Parties or their Affiliates (unless such portfolio operating company is acting at the direction of any one or more of the Irenic Parties or any of their Affiliates to engage in conduct prohibited by this Agreement); (b) the terms “beneficial owner” and “beneficially own” have the meanings set forth in Rule 13d-3 under the Exchange Act, except that a Person will also be deemed to be the beneficial owner of all shares of the Company’s capital shares that (i) such Person has the right to acquire (whether such right is exercisable immediately or only after the passage of time) pursuant to the exercise of any right in connection with any securities or any agreement, arrangement or understanding (whether or not in writing), regardless of when such rights may be exercised and whether they are conditional, and (ii) such Person or any of such Person’s Affiliates has or shares the right to vote or dispose; (c) the term “Business Day” means any day other than a Saturday, a Sunday or a day on which the Federal Reserve Bank of New York is closed; (d) the term “Common Stock” means the Company’s common stock, par value $0.01 per share; (e) the term “Control” (including the terms “Controlling,” “Controlled”, and “under common Control”) mean the possession, direct or indirect, of the power to direct or cause the direction of the management and policies of a Person, whether through the ownership of voting securities, by contract, or otherwise; (f) the term “Cooperation Period” means the period from the execution of this Agreement until the earlier of: (x) the one year anniversary of the Effective Date, and (y) the date that is thirty (30) calendar days prior to the notice deadline under the Organizational Documents for stockholders to submit stockholder nominations of director candidates for election to the Board (a “Nomination Notice Deadline”) at the Company’s 2027 Annual Meeting of Stockholders (the “2027 Annual Meeting”). (g) the term “Exchange Act” means the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated by the SEC;

13 1011705623v1 (h) the term “Group” has the meaning set forth in Section 13(d)(3) of the Exchange Act; (i) the term “Independent” means that such person qualifies as independent of the Company under all applicable listing standards, applicable rules of the SEC and publicly disclosed standards used by the Board in determining the independence of the Company’s directors, as disclosed to the Irenic Parties prior to the date hereof; (j) the term “Net Long Position” has the meaning set forth in Rule 14e-4 under the Exchange Act; (k) the terms “Person” or “Persons” shall mean any individual, corporation (including not-for-profit), general or limited partnership, limited liability or unlimited liability company, joint venture, estate, trust, association, organization or other entity of any kind or nature; (l) the term “Qualified Director” means an individual who (i) qualifies as Independent, (ii) unless the Company otherwise consents in its sole discretion (which is deemed granted as to the initial New Director by virtue of execution of this Agreement), (A) is not an employee, officer, director, general partner, manager or other agent of an Irenic Party or of any Affiliate of an Irenic Party, (B) is not a limited partner, member, or other investor (unless such investment is immaterial and has been disclosed to the Company) of or in any Irenic Party or any Affiliate of an Irenic Party, and (C) does not have any agreement, arrangement, or understanding, written or oral, with any Irenic Party or any Affiliate of an Irenic Party regarding such individual’s service as a director of the Company (unless any such agreement, arrangement, or understanding has been disclosed to the Company) and (iii) meets all other qualifications required for service as a director set forth in the Bylaws and the Company’s Corporate Governance Guidelines; (m) the term “Representatives” means a party’s directors, principals, members, general partners, managers, officers, employees, agents, advisors and other representatives; (n) the term “SEC” means the U.S. Securities and Exchange Commission; and (o) the term “Third Party” means any Person that is not a party to this Agreement or an Affiliate thereof, a director or officer of the Company, or legal counsel to any party to this Agreement. Section 8. Notices. Any notices, consents, determinations, waivers or other communications required or permitted to be given under the terms of this Agreement must be in writing and will be deemed to have been delivered: (A) upon receipt, when delivered personally; (B) when sent by email if during normal hours of a Business Day, otherwise on the next Business Day; provided that no “bounce back” or similar notice of non-delivery is received; or (C) one (1) Business Day after deposit with a nationally recognized overnight delivery service, in each case, properly addressed to the Party to receive the same. The addresses for such communications shall be: If to the Company:

14 1011705623v1 Atkore Inc. 16100 South Lathrop Avenue Harvey, IL 60426 Attention: Daniel S. Kelly, Esq; William E. Waltz; John Deitzer; Matthew Kline Email: DKelly@atkore.com; BWaltz@atkore.com; JDeitzer@atkore.com; MKline@atkore.com with a copy (which shall not constitute notice) to: Debevoise & Plimpton LLP 66 Hudson Boulevard New York, New York 10001 Attention: Benjamin R. Pedersen; Paul M. Rodel; William D. Regner Email: brpedersen@debevoise.com; pmrodel@debevoise.com; wdregner@debevoise.com If to the Irenic Parties: Irenic Capital Management L.P. 767 Fifth Avenue, 15th Floor New York, New York 10153 Attention: Josh Brodman Email: jbrodman@irenicmgmt.com with a copy (which shall not constitute notice) to: Willkie Farr & Gallagher LLP 787 Seventh Avenue New York, New York 10019 Attention: Maurice Lefkort, Esq.; Jared Fertman; Amanda M. Burke Email: Mlefkort@willkie.com; jfertman@willkie.com; aburke@willkie.com At any time, any party may, by notice given in accordance with this Section 8 to the other party, provide updated information for notices under this Agreement. Section 9. Expenses. All fees, costs and expenses incurred in connection with this Agreement and all matters related to this Agreement will be paid by the party incurring such fees, costs or expenses; provided, however, that the Company shall reimburse the Irenic Parties for their reasonable and documented out of pocket fees and expenses, including legal fees, incurred on or prior to the Effective Date and in connection with the Irenic Parties’ involvement at the Company, and including but not limited to, the preparation of the Nomination Notice and the negotiation and execution of this Agreement, in an amount not to exceed $300,000 in the aggregate.

15 1011705623v1 Section 10.Specific Performance; Remedies; Venue; Waiver of Jury Trial. (a) The Company and the Irenic Parties acknowledge and agree that irreparable injury to the other party would occur in the event any of the provisions of this Agreement were not performed in accordance with their specific terms or were otherwise breached and that such injury would not be adequately compensable by the remedies available at law (including the payment of money damages). It is accordingly agreed that the Company and the Irenic Parties will be entitled to an injunction or injunctions to prevent breaches of this Agreement and to enforce specifically the terms and provisions of this Agreement, in addition to any other remedy to which they are entitled at law or in equity. FURTHERMORE, THE COMPANY AND EACH IRENIC PARTY AGREES: (1) THE NON-BREACHING PARTY WILL BE ENTITLED TO INJUNCTIVE AND OTHER EQUITABLE RELIEF, WITHOUT PROOF OF ACTUAL DAMAGES; (2) THE BREACHING PARTY WILL NOT PLEAD IN DEFENSE THERETO THAT THERE WOULD BE AN ADEQUATE REMEDY AT LAW; AND (3) THE BREACHING PARTY WAIVES THE POSTING OF A BOND OR OTHER SECURITY UNDER ANY APPLICABLE LAW, IN THE CASE THAT ANY OTHER PARTY SEEKS TO ENFORCE THE TERMS BY WAY OF EQUITABLE RELIEF. (b) This Agreement will be governed in all respects, including validity, interpretation, and effect, by the laws of the State of Delaware without giving effect to the choice of law principles of such state. The Company and each Irenic Party (i) irrevocably and unconditionally submits to the exclusive jurisdiction of the Delaware Court of Chancery (or, only if the Delaware Court of Chancery declines to accept jurisdiction over a particular matter, the federal or other state courts located in Wilmington, Delaware), (ii) agrees that it will not attempt to deny or defeat such jurisdiction by motion or other request for leave from any such court, (iii) agrees that any action or proceeding based on, relating to, or arising in connection with this Agreement or the transactions contemplated by this Agreement shall be brought, tried, and determined only in such courts, (iv) waives any claim of improper venue or any claim that those courts are an inconvenient forum, and (v) agrees that it will not bring any action based on, relating to, or arising in connection with this Agreement or the transactions contemplated by this Agreement in any court other than such courts. The parties to this Agreement agree that the delivery of process or other papers based on, relating to, or arising in connection with any such action or proceeding in the manner provided in Section 8 or in such other manner as may be permitted by applicable law as sufficient service of process, shall be valid and sufficient service thereof; provided that such process or other papers based on, relating to, or arising in connection with any such action or proceeding is also contemporaneously delivered to the email address of such party set forth in Section 8 hereof (for the avoidance of doubt, such email shall not in and of itself constitute effective service of process). (c) EACH OF THE PARTIES, AFTER CONSULTING OR HAVING HAD THE OPPORTUNITY TO CONSULT WITH COUNSEL, KNOWINGLY, VOLUNTARILY, AND INTENTIONALLY WAIVES ANY RIGHT THAT SUCH PARTY MAY HAVE TO A TRIAL BY JURY IN ANY LITIGATION BASED ON, RELATING TO OR ARISING IN CONNECTION WITH THIS AGREEMENT OR ANY RELATED INSTRUMENT OR AGREEMENT, OR ANY OF THE TRANSACTIONS CONTEMPLATED THEREBY, OR ANY COURSE OF CONDUCT, DEALING, STATEMENTS (WHETHER ORAL OR WRITTEN), OR ACTIONS OF ANY OF THEM. NO PARTY SHALL SEEK TO

16 1011705623v1 CONSOLIDATE, BY COUNTERCLAIM OR OTHERWISE, ANY ACTION IN WHICH A JURY TRIAL HAS BEEN WAIVED WITH ANY OTHER ACTION IN WHICH A JURY TRIAL CANNOT BE OR HAS NOT BEEN WAIVED. Section 11.Severability. If, at any time subsequent to the Effective Date, any provision of this Agreement is held by any court of competent jurisdiction to be illegal, void or unenforceable, such provision will be of no force and effect, but the illegality, voidness or unenforceability of such provision will have no effect upon the legality or enforceability of any other provision of this Agreement. Section 12.Termination. This Agreement will terminate upon the expiration of the Cooperation Period; provided, however, that Section 2(a) will terminate upon the Company’s entry into a definitive written agreement with respect to an Extraordinary Transaction contemplated by clause (C) or (D) of the proviso in Section 2(d). Upon expiration of the Cooperation Period, this Agreement shall have no further force and effect. Notwithstanding anything to the contrary in the foregoing part of this Section 12, Sections 9 to 18 shall survive termination of this Agreement, and no termination of this Agreement shall relieve any party of liability for any breach of this Agreement arising prior to such termination. Section 13.Counterparts. This Agreement may be executed in counterparts, each of which shall be deemed to be an original, but both or all of which shall constitute the same agreement. Signatures to this Agreement transmitted by facsimile transmission, by electronic mail in “portable document format” (.pdf) form or by any other electronic means intended to preserve the original graphic and pictorial appearance of a document, will have the same effect as physical delivery of the paper document bearing the original signature. For the avoidance of doubt, no party shall be bound by any contractual obligation to the other parties until all counterparts to this Agreement have been duly executed by each of the parties and delivered to the other parties (including by means of electronic delivery). Section 14.Affiliates. Each of the Irenic Parties agrees that it will cause its Affiliates, and their respective employees and other Representatives, to comply with the terms of this Agreement. Section 15.No Third-Party Beneficiary. This Agreement is solely for the benefit of the Company and the Irenic Parties and is not enforceable by any other Person. No party to this Agreement may assign its rights or delegate its obligations under this Agreement, whether by operation of law or otherwise, without the prior written consent of the other parties in their respective sole discretions, and any assignment in contravention hereof will be null and void. Section 16.No Waiver. No failure or delay by any party in exercising any right or remedy under this Agreement will operate as a waiver thereof or of any breach of any provision hereof, nor will any single or partial waiver thereof preclude any other or further exercise thereof or the exercise of any other right or remedy under this Agreement. The failure of a party to insist upon strict adherence to any term of this Agreement on one or more occasions shall not be considered a waiver or deprive that party of the right thereafter to insist upon strict adherence to that term or any other term of this Agreement. No waiver shall be effective unless in writing, executed by the waiving party.

17 1011705623v1 Section 17.Entire Understanding; Amendment. This Agreement contains the entire understanding of the parties with respect to the subject matter hereof and supersedes any and all prior and contemporaneous agreements, memoranda, arrangements, and understandings, whether written or oral, between the parties, or any of them, with respect to the subject matter of this Agreement. This Agreement may be amended only by an agreement in writing executed by the Company and the Irenic Parties. Section 18.Interpretation and Construction. The Company and each Irenic Party acknowledges that it has been represented by counsel of its choice throughout all negotiations that have preceded the execution of this Agreement, and that it has executed the same after having had an adequate opportunity to seek the advice of said counsel. Each party and its counsel cooperated and participated in the drafting and preparation of this Agreement and the documents referred to herein, and any and all drafts relating thereto exchanged among the parties will be deemed the work product of all of the parties and may not be construed against any party by reason of its drafting or preparation. Accordingly, any rule of law or any legal decision that would require interpretation of any ambiguity in this Agreement against any party that drafted or prepared it is of no application and is hereby expressly waived by the Company and each Irenic Party, and any controversy over any interpretation of this Agreement will be decided without regard to events of drafting or preparation. Whenever the words “include,” “includes,” or “including” are used in this Agreement, they shall be deemed to be followed by the words “without limitation.” When a reference is made in this Agreement to any Section, such reference shall be to a Section of this Agreement, unless otherwise expressly indicated. The headings contained in this Agreement are for reference purposes only and shall not affect in any way the meaning or interpretation of this Agreement. The words “hereof,” “herein”, “hereto”, and “hereunder” and words of similar import when used in this Agreement shall refer to this Agreement as a whole and not to any particular provision of this Agreement. The word “will” shall be construed to have the same meaning as the word “shall.” The word “or” is not exclusive. The definitions contained in this Agreement are applicable to the singular as well as the plural forms of such terms. Any agreement, instrument, law, rule or statute defined or referred to herein means, unless otherwise indicated, such agreement, instrument, law, rule or statute as from time to time amended, modified or supplemented, except that references to specified rules promulgated by the SEC shall be deemed to refer to such rules in effect as of the date of this Agreement. [Signature pages follow]

[Signature Page to Cooperation Agreement] 1011705623v1 IN WITNESS WHEREOF, this Agreement has been duly executed and delivered by the duly authorized signatories of the parties as of the date hereof. IRENIC PARTIES IRENIC CAPITAL MANAGEMENT LP By: Irenic Capital Management GP LLC, its general partner By: /s/ Adam J. Katz Name: Adam J. Katz Title: Managing Member IRENIC CAPITAL MANAGEMENT GP LLC By: /s/ Adam J. Katz Name: Adam J. Katz Title: Managing Member IRENIC CAPITAL EVERGREEN FUND GP LLC By: /s/ Adam J. Katz Name: Adam J. Katz Title: Managing Member IRENIC CAPITAL EVERGREEN MASTER FUND LP By: Irenic Capital Management GP LLC, its general partner By: /s/ Adam J. Katz Name: Adam J. Katz Title: Managing Member

[Signature Page to Cooperation Agreement] 1011705623v1 ATKORE INC. By: /s/ William E. Waltz______________ Name: William E. Waltz Title: President and Chief Executive Officer

1011705623v1 Exhibit A Consulting Agreement

1011705623v1 Exhibit B Form of Press Release

Atkore Expands Scope of Strategic Alternatives Review to Maximize Shareholder Value Board and Management Team Will Consider Options Including a Potential Sale or Merger of Entire Company Enters into Cooperation Agreement with Irenic Capital Management; Will Expand Board of Directors 11/20/2025 HARVEY, Ill.--(BUSINESS WIRE)-- Atkore Inc. (“Atkore” or the “Company”) (NYSE: ATKR) today announced that its Board of Directors (the “Board”) has expanded the scope of its previously announced review of strategic alternatives to include assets outside of its core electrical infrastructure portfolio. As part of this expanded review, the Board and management team will consider a broader range of alternatives to maximize shareholder value, including, among other things, a potential sale or merger of the whole company. Bill Waltz, Atkore President and CEO said, “The Atkore Board remains steadfast in its commitment to maximize shareholder value, and has authorized Citi and J.P. Morgan Securities LLC to assist us in expanding the scope of our strategic review process.” “As the Board conducts its expanded strategic review process, management will continue to take actions to strengthen the business, including focusing on our core electrical infrastructure business and improving our cost structure to drive profitable growth,” said Atkore’s Chairman of the Board of Directors. There can be no assurance that the strategic alternatives review will result in the Company pursuing a transaction or any specific outcome. There is no deadline or definitive timetable set for completion of the strategic alternatives review. Atkore does not intend to make any further public comment on the process unless and until it determines that further disclosure is appropriate or necessary. Waltz continued, “Due to the Board’s decision to expand our strategic alternatives process, I have decided to stay on as CEO through at least the conclusion of the strategic review.” Board of Directors Update Atkore also announced today it will appoint Franklin Edmonds to its Board of Directors as part of a cooperation agreement with Irenic Capital Management LP (together with its affiliates, “Irenic”). With the addition of Mr. Edmonds, Atkore will expand its Board to ten directors, nine of whom will be independent. Additionally, the Board will form a Strategic Review Committee to oversee, evaluate and provide advice to the full Board regarding its review of strategic alternatives, including a potential sale or merger of the entire Company.

Once formed, Bruce Taten will be appointed to serve as a Special Advisor to the Strategic Review Committee. “We are pleased to welcome Frank to our Board,” said Michael Schrock, Chair of the Atkore Board of Directors. “Frank brings valuable industry perspective, coupled with extensive experience analyzing and investing in public and private enterprises, which will complement the current skillsets on the Board. We also look forward to benefiting from Bruce’s expertise on the Strategic Review Committee. We believe that Frank and Bruce will provide important insights as we conduct our thorough review to determine the best path forward for the Company and shareholders.” Pursuant to the cooperation agreement, Irenic has agreed to customary standstill and voting commitments, and other provisions. The cooperation agreement will be filed on a Current Report on Form 8-K with the U.S. Securities and Exchange Commission (the “SEC”). “We appreciate the Board’s collaborative approach, and we believe the Company is taking the right steps to achieve our shared goal of value creation,” said Adam Katz, Co-founder and Chief Investment Officer of Irenic. “Irenic invested in Atkore because we believe the Company is well positioned to successfully unlock significant value, and we believe the Board and the executive leadership team are committed to taking actions that advance the interests of all shareholders.” Advisors Citi is serving as lead financial advisor to Atkore, Debevoise & Plimpton LLP is serving as legal advisor and Joele Frank, Wilkinson Brimmer Katcher is serving as strategic communications advisor. J.P. Morgan Securities LLC is also serving as financial advisor to Atkore. Wilkie Farr & Gallagher LLP is serving as legal counsel and Longacre Square Partners is serving as strategy and communications advisor to Irenic. About Franklin Edmonds Franklin Edmonds is an experienced investor with broad industry expertise. He currently serves a Partner at Covey Hill, an investment firm. Prior to Covey Hill, he served as Head of Research and a Managing Partner at Panning Capital Management. He previously was a Partner at King Street Capital Management, where he was one of four members of the firm’s global Investment Committee. Earlier in his career, Mr. Edmonds also worked for Oak Hill Advisors and Lehman Brothers. He currently serves on the boards of the University of Virginia Investment Management Company (UVIMCO), the Darden Graduate School of Business and the Jefferson Scholars Foundation. Mr. Edmonds earned his bachelor’s degree, MBA and J.D. from The University of Virginia. About Bruce Taten Bruce Taten brings considerable experience as a public company director and more than two decades of corporate law expertise. Mr. Taten currently serves on the Board of Directors of Aviat Networks (NASDAQ: AVNW), where he serves as Chairman of the

Compensation Committee. He has also served on the Board of Directors of Jeld-Wen Holdings, Inc. (NYSE: JELD) since 2014, where he serves as Chair of the Governance and Nominating Committee and former chair of the Compensation Committee. Mr. Taten served as Senior Vice President, General Counsel and Chief Compliance Officer for Cooper Industries, plc from 2008 until its merger with Eaton Corporation in October 2012. Prior to Cooper Industries, Mr. Taten was Vice President and General Counsel at Nabors Industries from 2003 until 2008 and earlier practiced as an attorney with Simpson Thacher & Bartlett LLP and Sutherland Asbill & Brennan LLP. Mr. Taten holds a B.S. and Masters degree from Georgetown University and a J.D. from Vanderbilt University. About Atkore Inc. Atkore is a leading manufacturer of electrical products for commercial, industrial, data center, telecommunications, and solar applications. With 5,400 employees and $2.9B in sales in fiscal year 2025, we deliver sustainable solutions to meet the growing demands of electrification and digital transformation. To learn more, please visit www.atkore.com. About Irenic Capital Management Irenic Capital Management LP is an investment management firm founded by Adam Katz and Andy Dodge. Based in New York City, Irenic works collaboratively with publicly traded companies to ensure operating activities, capital deployment and management incentives are all aligned to create value for the company and its owners. For more information about Irenic, please visit www.irenicmgmt.com. Dissemination of Company Information Atkore intends to make future announcements regarding company developments and financial performance through its website, www.atkore.com, as well as through press releases, filings with the Securities and Exchange Commission, conference calls, media broadcasts, and webcasts. Forward-Looking Statements This press release contains “forward-looking statements” within the meaning of the Federal Private Securities Litigation Reform Act of 1995. Some of the forward-looking statements can be identified by the use of forward-looking terms such as “believes,” “expects,” “may,” “will,” “shall,” “should,” “would,” “could,” “seeks,” “aims,” “projects,” “is optimistic,” “intends,” “plans,” “estimates,” “anticipates” or other comparable terms. Forward-looking statements include, without limitation, statements about the Company’s review of strategic alternatives and all matters that are not historical facts. Forward-looking statements are subject to known and unknown risks and uncertainties, many of which may be beyond our control. Among the risks and uncertainties that could cause actual results to differ from those described in the forward-looking statements are the following: whether we will be able to identify or develop any strategic alternatives; our ability to execute on material aspects of any strategic alternatives that are identified and pursued; whether we can achieve the potential benefits of any strategic alternatives; the occurrence of any event, change or other circumstances that could give rise to the abandonment of the pursuit of a strategic alternative; risks related to potential litigation brought in connection with the review of strategic alternatives; uncertainties as to the timing of the review of strategic alternatives;

risks and costs related to the review of strategic alternatives; risks related to disruption of management time from ongoing business operations due to the review of strategic alternatives; and effects of the announcement, pendency or completion of the review of strategic alternatives on the ability of the Company to retain and hire key personnel and maintain relationships with its suppliers, and on its operating results and businesses generally. We caution you that forward-looking statements are not guarantees of future performance or outcomes and that actual performance and outcomes, including, without limitation, our actual results of operations, financial condition and liquidity, and the development of the market in which we operate, may differ materially from those made in or suggested by the forward-looking statements contained in this press release. In addition, even if our results of operations, financial condition and cash flows, and the development of the market in which we operate, are consistent with the forward-looking statements contained in this press release, those results or developments may not be indicative of results or developments in subsequent periods. A number of important factors, including, without limitation, the risks and uncertainties disclosed in the Company’s filings with the SEC including but not limited to the Company’s most recent Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K could cause actual results and outcomes to differ materially from those reflected in the forward-looking statements. The Company assumes no obligation to update the information contained herein, which speaks only as of the date hereof. Investor Contact: Matthew Kline Vice President – Treasury & Investor Relations 708-225-2116 Investors@atkore.com Media Contact: Lisa Winter Vice President – Communications 708-225-2453 AtkoreCommunications@atkore.com For Irenic: Longacre Square Partners Irenic@Longacresquare.com with a copy to: Willkie Farr & Gallagher LLP Maurice Lefkort; Jared Fertman; Amanda M. Burke mlefkort@willkie.com; jfertman@willkie.com; aburke@willkie.com Source: Atkore Inc.