Damek.

I’d always assumed they were legal, but apparently they’re not.

Temporary signage, whether on construction sidewalk sheds or on scrim that covers temporary work, must have a permit from the Department of Buildings and comply with the city’s zoning regulations on signage. Almost all oversized signs on buildings are illegal unless they are in Times Square or on Seventh Avenue at 34th Street. Houston Street is also by and large excepted from the regulations.

I wonder if 86th Street is largely excepted from the regs? In any case, I think I’ll heed their suggestion and start calling 311 “with the exact address of the building” when I see one.