As a Part 107 pilot and property manager, how to I get a waiver to fly in the DC-SFRA to do roof inspections, etc.
The appropriate site to apply for a waiver to operate within the FRZ (inner ring) of the DC SFRA can be found here. A TSA/FAA waiver and SGI (Special Government Interest)/COA (Certificate of Authorization) are required to operate within the FRZ.
I am Part 107 as well. You have to get a waiver from the FAA. You cannot get it through LAANC. A call to the FSDO may be a good start. They will clear you for a specific date and time and assign an altitude restriction. There may be a TSA background check as well similar to flights in the FRZ.