I have no idea about the foam coating.
As for the roof of your pub, two things that might help the save the owner a fortune,
1/ I have seen roof repairs where the rubbish is replaced and a flashing fits over at least three pans of the new roof and three pans of the existing. This is of course monoclad/speed deck style roofing only, not custom orb.
2/ If the rest of the roof is ok, steal sheets from the edge roof towards your problem, use them to replace around aircon. Install new sheets in that area, and then use the above to seal between new and old.
Now I’m in Brisbane so my summer storms are less than yours, so maybe you need five pans in each direction
The other thing is I still have
All advice is given with-out seeing the job, and hence all advice MUST be taken as advice with limited knowledge on the exact situation. NO responsibility can or will be taken. And yes, I am a licensed Plumber and Drainer with my own business in Brisbane Australia