<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019f8060-f18c-7450-8c87-00e644bf5386,g:3eb241c4-4d9b-4f54-a6a0-418188ccb388-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.limbachinc.com/role/Cover" xlink:type="simple" xlink:href="lmb-20260724.xsd#Cover"/>
  <link:definitionLink xlink:role="http://www.limbachinc.com/role/Cover" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable_019f8060-f18c-7bdd-8ef0-6693dadeec26" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_DocumentInformationTable_019f8060-f18c-7bdd-8ef0-6693dadeec26" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressesAddressTypeAxis_019f8060-f18c-7403-8638-eb18e1fc3f50" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressesAddressTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_019f8060-f18c-7bdd-8ef0-6693dadeec26" xlink:to="loc_dei_EntityAddressesAddressTypeAxis_019f8060-f18c-7403-8638-eb18e1fc3f50" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AddressTypeDomain_019f8060-f18c-7403-8638-eb18e1fc3f50_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AddressTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_EntityAddressesAddressTypeAxis_019f8060-f18c-7403-8638-eb18e1fc3f50" xlink:to="loc_dei_AddressTypeDomain_019f8060-f18c-7403-8638-eb18e1fc3f50_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AddressTypeDomain_019f8060-f18c-704e-bf0e-2a6153be29f4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AddressTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_EntityAddressesAddressTypeAxis_019f8060-f18c-7403-8638-eb18e1fc3f50" xlink:to="loc_dei_AddressTypeDomain_019f8060-f18c-704e-bf0e-2a6153be29f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_FormerAddressMember_019f8060-f18c-7e53-90bd-15449aed8141" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_FormerAddressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_AddressTypeDomain_019f8060-f18c-704e-bf0e-2a6153be29f4" xlink:to="loc_dei_FormerAddressMember_019f8060-f18c-7e53-90bd-15449aed8141" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019f8060-f18c-7380-9083-04d13b1da536" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_DocumentType_019f8060-f18c-7380-9083-04d13b1da536" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019f8060-f18c-7af7-976d-cb31c1f67c5f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_DocumentPeriodEndDate_019f8060-f18c-7af7-976d-cb31c1f67c5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019f8060-f18c-768c-99ff-fc6584a842e5" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_EntityRegistrantName_019f8060-f18c-768c-99ff-fc6584a842e5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019f8060-f18c-7e1e-be3c-48313566052f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019f8060-f18c-7e1e-be3c-48313566052f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019f8060-f18c-75ad-8c2d-5e374afd9a48" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_EntityFileNumber_019f8060-f18c-75ad-8c2d-5e374afd9a48" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019f8060-f18c-7986-a35f-2e6b8df93db5" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_EntityTaxIdentificationNumber_019f8060-f18c-7986-a35f-2e6b8df93db5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019f8060-f18c-7186-8f70-5e77cb20a76c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_EntityAddressAddressLine1_019f8060-f18c-7186-8f70-5e77cb20a76c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine2_019f8060-f18c-7b49-b35b-3be8eb106a8f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_EntityAddressAddressLine2_019f8060-f18c-7b49-b35b-3be8eb106a8f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019f8060-f18c-7d26-805a-1154b3a700cd" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_EntityAddressCityOrTown_019f8060-f18c-7d26-805a-1154b3a700cd" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019f8060-f18c-782b-97bd-f740865f1e39" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_EntityAddressStateOrProvince_019f8060-f18c-782b-97bd-f740865f1e39" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019f8060-f18c-7a27-957a-666e6dc06e83" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_EntityAddressPostalZipCode_019f8060-f18c-7a27-957a-666e6dc06e83" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019f8060-f18c-7ad3-a9c5-7fdaacb10af0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_CityAreaCode_019f8060-f18c-7ad3-a9c5-7fdaacb10af0" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019f8060-f18c-7e70-b246-69f503645a10" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_LocalPhoneNumber_019f8060-f18c-7e70-b246-69f503645a10" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_019f8060-f18c-7fb3-9200-29cafd42fcbe" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_WrittenCommunications"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_WrittenCommunications_019f8060-f18c-7fb3-9200-29cafd42fcbe" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_019f8060-f18c-70a9-a4b6-98fd692f296c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SolicitingMaterial"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_SolicitingMaterial_019f8060-f18c-70a9-a4b6-98fd692f296c" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_019f8060-f18d-712a-96fd-16cda416b8ee" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_PreCommencementTenderOffer_019f8060-f18d-712a-96fd-16cda416b8ee" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_019f8060-f18d-7920-b8c6-1887b97cc2c0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_019f8060-f18d-7920-b8c6-1887b97cc2c0" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019f8060-f18d-7121-8668-1fff7ffcc270" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_Security12bTitle_019f8060-f18d-7121-8668-1fff7ffcc270" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019f8060-f18d-7a1b-b292-fd6427960525" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_TradingSymbol_019f8060-f18d-7a1b-b292-fd6427960525" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019f8060-f18d-7fb1-90e9-05fc5adecedb" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_SecurityExchangeName_019f8060-f18d-7fb1-90e9-05fc5adecedb" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019f8060-f18d-7e9f-8220-0d43a32621ac" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_EntityEmergingGrowthCompany_019f8060-f18d-7e9f-8220-0d43a32621ac" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019f8060-f18d-7d6a-9ec4-21093b2795d8" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_AmendmentFlag_019f8060-f18d-7d6a-9ec4-21093b2795d8" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019f8060-f18d-7a6d-a523-3d4f64bd615a" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_EntityCentralIndexKey_019f8060-f18d-7a6d-a523-3d4f64bd615a" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_019f8060-f18d-7ab9-a48d-af4c01b2a67e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8060-f18c-7801-a8ea-305eaadcd36f" xlink:to="loc_dei_CurrentFiscalYearEndDate_019f8060-f18d-7ab9-a48d-af4c01b2a67e" xlink:type="arc" order="23"/>
  </link:definitionLink>
</link:linkbase>
