Regulation FD Disclosure On September 1, 2026, Limbach Holdings, Inc. (the “Company”) issued a press release announcing the closing of the acquisition of Madison, Wisconsin-based mechanical contractor, 1901 Inc., for an initial purchase price at closing of $63.0 million to be paid through a combination of available cash and borrowings under the Company’s recently expanded revolving credit facility. The transaction also includes performance-based earnouts of up to $6.0 million, with the earnou…

Results of Operations and Financial Condition. On August 4, 2026, Limbach Holdings, Inc. (the “Company”) issued a press release dated the same date announcing its financial results for the quarter ended June 30, 2026. A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

Regulation FD Disclosure. Also on August 4, 2026, the Company issued a press release announcing the closing of its acquisition of Frisco, Texas-based professional services firm, CYMCOR, Inc., for an initial purchase price at closing of $30.0 million to be paid through a combination of available cash and the Company’s revolving credit facility. A copy of the press release is furnished as Exhibit 99.2 to this Current Report on Form 8-K and is incorporated herein by reference. In addition, the C…

Entry into a Material Definitive Agreement On July 24, 2026, Limbach Facility Services LLC (“Borrower”), a wholly owned subsidiary of Limbach Holdings, Inc. (“LHI”), Limbach Holdings LLC, a wholly owned subsidiary of LHI, and certain other loan parties thereto entered into the Third Amendment to the Second Amended and Restated Credit Agreement (the “Third Amendment to the Credit Agreement”) with Wheaton Bank & Trust Company, N.A., a subsidiary of Wintrust Financial Corporation, as administrat…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant The information included in

Executive Vice President and Chief Operating Officer — Michael J. Reed: Michael J. Reed was promoted to Executive Vice President and Chief Operating Officer.

Results of Operations and Financial Condition. On May 5, 2026, Limbach Holdings, Inc. (the “Company”) issued a press release dated the same date announcing its financial results for its quarter ended March 31, 2026. We have furnished a copy of this release as Exhibit 99.1 to this Current Report on Form 8-K.

Results of Operations and Financial Condition. On March 2, 2026, Limbach Holdings, Inc. (the “Company”) issued a press release dated the same date announcing its financial results for its year ended December 31, 2025. We have furnished a copy of this release as Exhibit 99.1 to this Current Report on Form 8-K.

Director — Terence P. Dugan: Appointment of Terence P. Dugan as an Independent Director.

Other Events On December 15, 2025, Limbach Holdings, Inc. (the “Company”) announced that its board of directors authorized a share repurchase program (the “Share Repurchase Program”), pursuant to which the Company may, from time to time, purchase up to $50.0 million of shares of its common stock through December 15, 2027. Share repurchases may be executed through various means, including, without limitation, open market transactions, privately negotiated transactions or by other means in acco…

Results of Operations and Financial Condition. On November 4, 2025, Limbach Holdings, Inc. (the “Company”) issued a press release dated the same date announcing its financial results for its quarter ended September 30, 2025. We have furnished a copy of this release as Exhibit 99.1 to this Current Report on Form 8-K.

Regulation FD Disclosure On August 7, 2025 and as it relates to Limbach Holdings, Inc.’s (the “Company”) recently completed acquisition of Pioneer Power, Inc. (“PPI”), the Company prepared and made available a set of Frequently Asked Questions (“FAQs”) to address inquiries from employees, customers, and other stakeholders regarding the PPI acquisition and certain aspects of its expected impact. The FAQs are intended to provide general information and do not constitute legal, financial, or inv…

Results of Operations and Financial Condition. On August 5, 2025, Limbach Holdings, Inc. (the “Company”) issued a press release dated the same date announcing its financial results for its quarter ended June 30, 2025. We have furnished a copy of this release as Exhibit 99.1 to this Current Report on Form 8-K.

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant To the extent applicable, the information included in

Regulation FD Disclosure On July 1, 2025, Limbach Holdings, Inc. (the “Company”) issued a press release announcing the closing of the acquisition of Woodbury, Minnesota-based mechanical contractor, Pioneer Power, Inc., for an initial purchase price at closing of $66.1 million to be paid through a combination of available cash and the Company’s revolving credit facility. The information in this Current Report on Form 8-K and the Exhibit 99.1 attached hereto shall not be deemed “filed” for purp…

Entry into a Material Definitive Agreement On June 27, 2025, Limbach Facility Services LLC (“Borrower”), Limbach Holdings LLC, and other designated parties entered into a second amendment to the Second A&R Wintrust Credit Agreement (the “Second Amendment to the Second A&R Wintrust Credit Agreement”) with Wheaton Bank & Trust Company, N.A., a subsidiary of Wintrust Financial Corporation (collectively, “Wintrust”), as administrative agent, and the other lenders party thereto, which amends that…

Other Events Amendments to the Omnibus Plan As noted above, on June 11, 2025, at the Annual Meeting, the stockholders of the Company approved the amendment no: 6 to the Omnibus Plan (the “Plan Amendment”) related to the treatment of death, disability, retirement and reduction in force as it relates to the Omnibus Plan participants. The Plan Amendment is designed to apply certain acceleration provisions for death, disability, and retirement to awards under the Omnibus Plan. In addition to othe…

Results of Operations and Financial Condition. On May 5, 2025, Limbach Holdings, Inc. (the “Company”) issued a press release dated the same date announcing its financial results for its quarter ended March 31, 2025. We have furnished a copy of this release as Exhibit 99.1 to this Current Report on Form 8-K.

Results of Operations and Financial Condition. On March 10, 2025, Limbach Holdings, Inc. (the “Company”) issued a press release dated the same date announcing its financial results for its year ended December 31, 2024. We have furnished a copy of this release as Exhibit 99.1 to this Current Report on Form 8-K.

The filing describes the adoption of a severance plan and approval of new equity award forms, which are routine corporate actions.

Regulation FD Disclosure On December 2, 2024, Limbach Holdings, Inc. issued a press release announcing the closing of the acquisition of Owensboro, Kentucky-based specialty mechanical contractor, Consolidated Mechanical, Inc., for an initial purchase price of $23.0 million to be paid in cash. The transaction also provides for an earnout of up to $2.0 million. The information in this Current Report on Form 8-K and the exhibit attached hereto shall not be deemed “filed” for purposes of Section…

Results of Operations and Financial Condition. On November 5, 2024, Limbach Holdings, Inc. (the “Company”) issued a press release dated the same date announcing its financial results for its quarter ended September 30, 2024. We have furnished a copy of this release as Exhibit 99.1 to this Current Report on Form 8-K.

Regulation FD Disclosure On September 3, 2024, Limbach Holdings, Inc. issued a press release announcing the closing of the acquisition of Laurel, MD-based specialty mechanical contractor, Kent Island Mechanical, LLC, for an initial purchase price of $15 million to be paid in cash. The transaction also provides for an earnout of up to $5.0 million. The information in this Current Report on Form 8-K and the exhibit attached hereto shall not be deemed “filed” for purposes of Section 18 of the Se…

Results of Operations and Financial Condition. On August 6, 2024, Limbach Holdings, Inc. (the “Company”) issued a press release dated the same date announcing its financial results for its quarter ended June 30, 2024. We have furnished a copy of this release as Exhibit 99.1 to this Current Report on Form 8-K.

Results of Operations and Financial Condition. On May 8, 2024, Limbach Holdings, Inc. (the “Company”) issued a press release dated the same date announcing its financial results for its quarter ended March 31, 2024. We have furnished a copy of this release as Exhibit 99.1 to this Current Report on Form 8-K.