The Sterling Group, an operationally focused middle market private equity firm, completed the acquisition of L&S Mechanical, a tri-trade provider of turnkey plumbing, HVAC and electrical installation services. Financial terms were not disclosed. "Thomas Mozjesik and his team pioneered the tri-trade model in Texas. We are excited to partner with the team to continue to expand that model in both Texas and other states," Greg Elliott, The Sterling Group Partner.