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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported) August 1, 2013 (July 31, 2013)

GIBRALTAR INDUSTRIES, INC.

(Exact name of registrant as specified in its charter)

3556 Lake Shore Road

P.O. Box 2028

Buffalo, New York 14219-0228

(Address of principal executive offices) (Zip Code)

(716) 826-6500

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

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and

The following information is furnished pursuant to both Item 2.02 and Item 7.01:

On August 1, 2013, Gibraltar Industries, Inc. (the “Company”) issued a news release and held a conference call regarding results for the three and six months ended June 30, 2013. A copy of the news release (the “Release”) is furnished herewith as Exhibit 99.2 and is incorporated herein by reference.

The Company references non-GAAP financial information in both the Release and the conference call. A reconciliation of these non-GAAP financial measures is contained in the Release. The information in this Form 8-K under the captions Items 2.02 and 7.01 and Item 9.01, including the Release, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to liabilities under that Section and shall not be deemed to be incorporated by reference into any filing of the Company under the Securities Act of 1933 (the “Securities Act”) or the Exchange Act, unless the Company specifically incorporates it by reference in a document filed under the Securities Act or the Exchange Act.

On July 31, 2013, the registrant announced that it had commenced an exchange offer to exchange its outstanding 6.25% Senior Subordinated Notes due 2021, issued in January 2013, for a like principal amount of its 6.25% Senior Subordinated Notes due 2021, registered under the Securities Act of 1933. A copy of the press release issued in connection with such action is furnished here with as Exhibit 99.1.

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SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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