WITNESSETH:

Exhibit 4.1

CONFORMED COPY

THIRTEENTH SUPPLEMENTAL INDENTURE (this “Thirteenth Supplemental Indenture”), dated as of April 10, 2015, among MASTEC, INC., a Florida corporation (the “Company”), the guarantors party hereto (the “Guarantors”) and U.S. BANK NATIONAL ASSOCIATION, as trustee under the Indenture referred to below (the “Trustee”).

WITNESSETH:

WHEREAS, the Company has heretofore executed and delivered to the Trustee an indenture (as amended, supplemented or otherwise modified, the “Indenture”), dated as of June 5, 2009, providing for (i) the issuance by the Company from time to time of its senior debt securities evidencing its unsecured and unsubordinated indebtedness, in an unlimited aggregate principal amount, in one or more series and (ii) the guaranty of such securities by the guarantors party thereto;

WHEREAS, the Company has heretofore supplemented the Indenture by, among other things, executing and delivering to the Trustee (i) the Fifth Supplemental Indenture, dated as of March 18, 2013 (the “Fifth Supplemental Indenture”), by and among the Company, the guarantors party thereto and the Trustee, relating to the Company’s 4.875% Senior Notes due 2023 (the “Notes”), (ii) the Sixth Supplemental Indenture, dated as of September 30, 2013, by and among the Company, the guarantors party thereto and the Trustee, relating to the joinder of certain subsidiaries of the Company as subsidiary guarantors, (iii) the Seventh Supplemental Indenture, dated as of November 11, 2013, by and among the Company, the guarantors party thereto and the Trustee, relating to the joinder of certain subsidiaries of the Company as subsidiary guarantors, (iv) the Tenth Supplemental Indenture, dated as of July 10, 2014, by and among the Company, the guarantors party thereto and the Trustee, relating to the joinder of certain subsidiaries of the Company as subsidiary guarantors, (v) the Eleventh Supplemental Indenture, dated as of August 8, 2014, by and among the Company, the guarantors party thereto and the Trustee, relating to the joinder of certain subsidiaries of the Company as guarantors and (vi) the Twelfth Supplemental Indenture, dated as of December 8, 2014, by and among the Company, the guarantors party thereto and the Trustee, relating to the joinder of certain subsidiaries of the Company as guarantors;

WHEREAS, the Issuer has solicited (the “Consent Solicitation”) the Holders to direct the Trustee to execute and deliver an amendment to the Indenture to amend certain definitions in Article 1 of the Fifth Supplemental Indenture, certain covenants in Article 4 of the Fifth Supplemental Indenture, certain terms in Article 9 of the Fifth Supplemental Indenture and to waive certain defaults, breaches or non-compliance (the “Amendment”);

WHEREAS, Section 9.02 of the Fifth Supplemental Indenture provides that the Company may amend or supplement the Indenture with the consent of the Holders of not less than a majority in aggregate principal amount of the then outstanding Notes (the “Requisite Consents”);

WHEREAS, in connection with the Consent Solicitation, Holders that delivered and have not withdrawn a valid consent to the amendments on a timely basis (the “Consenting Holders”) are entitled to receive consent fees (the “Consent Fees”) with respect to the Notes in respect of which they have validly consented if the conditions to the Consent Solicitation are met;

WHEREAS, the Holders that have approved this Thirteenth Supplemental Indenture (as evidenced by their execution of a Consent Form) constitute Holders of not less than a majority in aggregate principal amount of the Notes now outstanding and are willing to direct the Trustee to execute and deliver this Supplemental Indenture;

WHEREAS, consistent with the practice of the Depository Trust Company (“DTC”), DTC has authorized direct participants in DTC set forth in the position listing of DTC as of the date hereof to approve this Supplemental Indenture as if they were Holders of the Notes held of record in the name of DTC or the name of its nominee;

WHEREAS, the Trustee is hereby directed by the Holders of the requisite principal amount of Notes to execute and deliver this Thirteenth Supplemental Indenture in its capacity as Trustee; and

WHEREAS, the execution and delivery of this Thirteenth Supplemental Indenture have been duly authorized by the Company and all conditions and requirements necessary to make this instrument a valid and binding agreement have been duly performed and complied with.

NOW, THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the Company, the Guarantors and the Trustee mutually covenant and agree for the equal and ratable benefit of the holders of the Notes as follows:

2

“Whether or not the Company is then required to file reports with the SEC, the Company shall file with the SEC all such reports and other information as it would be required to file with the SEC by Section 13(a) or 15(d) under the Exchange Act (the “SEC Required Information”) if it were subject thereto, no later than 15 days after the respective dates by which such reports would be required to be filed under the SEC’s rules and regulations.”

“Notwithstanding the foregoing, the Company shall not be required to file with the SEC or supply to the Trustee (i) any applicable SEC Required Information, including, but not limited to, the 2014 Form 10-K and the Q1 2015 Form 10-Q, prior to the Initial Reporting Extension Date or (ii) if the Reporting Extension Date is the Second Reporting Extension Date, any applicable SEC Required Information, including, but not limited to, the 2014 Form 10-K, the Q1 2015 Form 10-Q and the Q2 2015 Form 10-Q, prior to the Second Reporting Extension Date.”

“Notwithstanding the foregoing or any other provision of this Indenture, the Company shall have no obligation to deliver the Officers’ Certificate required by this Section 4.04(a) relating to the fiscal year ended December 31, 2014 until the Initial Reporting Extension Date or, if applicable, the Second Reporting Extension Date.”

“Notwithstanding the foregoing or any other provision of this Indenture, the Company shall have no obligation to deliver the Officer’s Certificate required by this Section 4.04(b) relating to any breach of or failure to comply with Section 4.03 or Section 4.04(a) that occurred prior to the Initial Reporting Extension Date, or, if applicable, the Second Reporting Extension Date.”

“After an amendment, supplement or waiver under this Section 9.02 becomes effective, the Company shall either (i) mail to Holders affected thereby a notice or (ii) issue a press release, in either case, briefly describing the amendment, supplement or waiver. Any failure of the Company to mail such notice or issue such press release, or any defect therein, shall not, however, in any way impair or affect the validity of any such supplemental indenture.”

3

4

IN WITNESS WHEREOF, the parties hereto have caused this Thirteenth Supplemental Indenture to be duly executed as of the date first above written.

[Signature Page to Thirteenth Supplemental Indenture]

[Signature Page to Thirteenth Supplemental Indenture]

[Signature Page to Thirteenth Supplemental Indenture]

[Signature Page to Thirteenth Supplemental Indenture]