ROCK Gibraltar Industries, Inc. - 8-K/A

Item 9.01

Financial Statements and Exhibits.

(a) Financial Statements of Businesses Acquired.

The audited financial statements of OmniMax (a wholly owned indirect subsidiary of Arundel) as of and for the years ended December 31, 2025 and 2024 are filed as Exhibit
99.1 to this Form 8-K/A and incorporated herein by reference.

(b) Pro Forma Financial Information.

The unaudited pro forma combined financial information of Gibraltar and OmniMax as of and for the year ended December 31, 2025 and the related notes are filed as Exhibit
99.2 to this Form 8-K/A and incorporated herein by reference.

(d) Exhibits.

Exhibit No.

Document Description

99.1

Audited Financial Statements of OmniMax as of and for the Years Ended December 31, 2025 and 2024

99.2

Unaudited Pro Forma Combined Financial Information of Gibraltar and OmniMax as of and for the Year Ended December 31, 2025

104

Cover Page Interactive Data File (formatted as Inline XBRL)