In Florida General contractors can only do roofing work in-house (with their own employees) when installing shingles on structures for which they pulled the building permit.
General Contractors are also allowed to do warranty work on the roofing system of the properties they have built.
Florida Statute 489 Section 113, Qualifications for practices; restrictions - (b)(3) says: "A general, building, or residential contractor shall not be required to subcontract the installation, or repair made under warranty, of wood shingles, wood shakes, or asphalt or fiberglass shingle roofing materials on a new building of his or her own construction."
You guessed it; you need a Roofing Contractor’s License. This license allows to work on any roof regardless of whether it is new construction, repair, commercial, residential, tile, shingle, built-up or any type other type of roof.