<SEC-DOCUMENT>0001628280-20-013408.txt : 20200909
<SEC-HEADER>0001628280-20-013408.hdr.sgml : 20200909
<ACCEPTANCE-DATETIME>20200909171725
ACCESSION NUMBER:		0001628280-20-013408
CONFORMED SUBMISSION TYPE:	3/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20200904
FILED AS OF DATE:		20200909
DATE AS OF CHANGE:		20200909

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			McCann Michael M
		CENTRAL INDEX KEY:			0001760470

	FILING VALUES:
		FORM TYPE:		3/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36541
		FILM NUMBER:		201167155

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

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>3/A
<SEQUENCE>1
<FILENAME>wf-form3a_159968622645067.xml
<DESCRIPTION>FORM 3/A
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3/A</documentType>

    <periodOfReport>2020-09-04</periodOfReport>

    <dateOfOriginalSubmission>2019-01-01</dateOfOriginalSubmission>

    <noSecuritiesOwned>0</noSecuritiesOwned>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001760470</rptOwnerCik>
            <rptOwnerName>McCann Michael M</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>Chief Operating Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4000.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This Form 3 is being amended to include information previously not reported on a Form 3 filed January 1, 2019 (the &quot;Initial Form 3&quot;). The Initial Form 3 did not include 4,000 market-based RSUs granted on August 30, 2017. As amended, this award will vest upon the achievement of specified target share price of the Company's common stock on the Nasdaq Capital Market or other applicable principal securities exchange on which the Company's shares are then listed between August 1, 2018 and July 16, 2022, subject to continued employment from August 1, 2017 through the later of July 31, 2019 and the date on which the Compensation Committee of the Board of Directors certifies the achievement of the performance goal.</footnote>
        <footnote id="F2">Each restricted stock unit (&quot;RSU&quot;) represents a contingent right to receive one share of Limbach Holdings, Inc. (the &quot;Company&quot;) common stock, exempt under Rule 16b-3.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jeremiah G. Garvey, Attorney-in-Fact for Michael M. McCann</signatureName>
        <signatureDate>2020-09-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
