<SEC-DOCUMENT>0001628280-21-000077.txt : 20210105
<SEC-HEADER>0001628280-21-000077.hdr.sgml : 20210105
<ACCEPTANCE-DATETIME>20210105164849
ACCESSION NUMBER:		0001628280-21-000077
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20201231
FILED AS OF DATE:		20210105
DATE AS OF CHANGE:		20210105

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Brooks Jayme L.
		CENTRAL INDEX KEY:			0001447591

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36541
		FILM NUMBER:		21506562

	MAIL ADDRESS:	
		STREET 1:		21211 NORDHOFF STREET
		CITY:			CHATSWORTH
		STATE:			CA
		ZIP:			91311

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Limbach Holdings, Inc.
		CENTRAL INDEX KEY:			0001606163
		STANDARD INDUSTRIAL CLASSIFICATION:	CONSTRUCTION SPECIAL TRADE CONTRACTORS [1700]
		IRS NUMBER:				000000000
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1251 WATERFRONT PLACE
		STREET 2:		SUITE 201
		CITY:			PITTSBURGH
		STATE:			PA
		ZIP:			15222
		BUSINESS PHONE:		(412) 359-2100

	MAIL ADDRESS:	
		STREET 1:		1251 WATERFRONT PLACE
		STREET 2:		SUITE 201
		CITY:			PITTSBURGH
		STATE:			PA
		ZIP:			15222

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	1347 Capital Corp
		DATE OF NAME CHANGE:	20140422
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_160988331509935.xml
<DESCRIPTION>FORM 4
<TEXT>
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    <periodOfReport>2020-12-31</periodOfReport>

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    <issuer>
        <issuerCik>0001606163</issuerCik>
        <issuerName>Limbach Holdings, Inc.</issuerName>
        <issuerTradingSymbol>LMB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001447591</rptOwnerCik>
            <rptOwnerName>Brooks Jayme L.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1251 WATERFRONT PL, STE 201</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PITTSBURGH</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>15222</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP &amp; Chief Financial Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

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                <value>Common Stock</value>
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                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionAmounts>
                <transactionShares>
                    <value>2000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
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                <sharesOwnedFollowingTransaction>
                    <value>43530</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
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            <transactionDate>
                <value>2021-01-01</value>
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                <transactionCode>M</transactionCode>
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                <sharesOwnedFollowingTransaction>
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        </nonDerivativeTransaction>
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                <transactionAcquiredDisposedCode>
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            <expirationDate>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2000.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>20000</value>
                </sharesOwnedFollowingTransaction>
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                </directOrIndirectOwnership>
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                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
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                    <value>3333.0</value>
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                <sharesOwnedFollowingTransaction>
                    <value>16667</value>
                </sharesOwnedFollowingTransaction>
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                    <value>D</value>
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        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
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                <value>2021-01-01</value>
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                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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                <transactionShares>
                    <value>10000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
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                <footnoteId id="F4"/>
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                <underlyingSecurityTitle>
                    <value>Common Stock</value>
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                <underlyingSecurityShares>
                    <value>10000.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
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                <sharesOwnedFollowingTransaction>
                    <value>26667</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
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        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each restricted stock unit (&quot;RSU&quot;) represents a contingent right to receive one share of Limbach Holdings, Inc. common stock, exempt under Rule 16b-3.</footnote>
        <footnote id="F2">As reported in the original filing of this Form 4 on October 1, 2019, this award of RSUs was granted on October 1, 2019. 42,215 shares of common stock subject to this award were subject to service-based vesting conditions and vested on October 1, 2020. 6,000 shares of common stock subject to this award are subject to service-based vesting conditions and vest in equal annual installments on each of December 31, 2020, 2021 and 2022, subject to continued service through such vesting date. The remaining 6,000 shares of common stock subject to this award shall vest upon the Company's achievement of certain performance milestones, subject to Participant's continuous service with the Company or a subsidiary or affiliate of the Company, as applicable, as an employee through the certification by the Compensation Committee of the achievement of such performance milestones, if applicable.</footnote>
        <footnote id="F3">This award of RSUs was granted on 01/01/2020. The award is subject to service-based vesting conditions and vests in equal annual installments on each of January 1, 2021, January 1, 2022 and January 1, 2023, subject to continued employment through the applicable vesting date. The amounts reported above (related to this grant) do not include performance-based RSUs, if any, that may be earned by the reporting person but for which the Compensation Committee has not yet determined the achievement of the applicable performance goals. Any such RSUs will be reported on a Form 4 within two business days of the date of such determination.</footnote>
        <footnote id="F4">This award of RSUs was granted on 1/1/2021. The award is subject to service-based vesting conditions and vests in equal annual installments on each of January 1, 2022, January 1, 2023 and January 1, 2024, subject to continued employment through the applicable vesting date. The amounts reported above (related to this grant) do not include performance-based RSUs, if any, that may be earned by the reporting person but for which the Compensation Committee has not yet determined the achievement of the applicable performance goals. Any such RSU's will be reported on a Form 4 within two business days of the date of such determination.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jeremiah G. Garvey, Attorney-in-Fact for Jayme L. Brooks</signatureName>
        <signatureDate>2021-01-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
