Some type of Liability insurance generally higher than most carry, you would need to speak to your agent and explain your interest in using a UAS in your profession you may need to expand your coverage. Again your really treading a thin line with your knowledge of the subject and what must be in place before proceeding if you wish to go forward in this sector of commercial operations... That was said with no malice...just letting you know before you get a serious fine or such. Far to many people in the insurance/roofing and reality professions just buy and fly with no knowledge of what they are doing in accordance of the laws.
A mavic mini requires no registration (In US) when flying for hobby. BUT your flying commercial...and you must register it and obtain a 107 Certification (Commercial endorsement). And thus carry Insurance for that operation. I know many "pilots" that fly with their systems and carry a million dollar rider provision, but they aren't filming houses (Well some do)
For instance...your flying your mini and the wind gets it, it flails into the neighbors yard where small children are playing..it smacks a toddler in the face and cuts his eye cornea, thus blinding him for life...do you have enough insurance to cover that lawsuit? Worst case scenario possibly...but plausible, thus the reason people carry insurance in the first place.