Section 6. The local inspector, immediately upon being informed by report or otherwise that a building or other structure or anything attached thereto or connected therewith in that city or town is dangerous to life or limb or that any building in that city or town is unused, uninhabited or abandoned, and open to the weather, shall inspect the same; and he shall forthwith in writing notify the owner, lessee or mortgagee in possession to remove it or make it safe if it appears to him to be dangerous, or to make it secure if it is unused, uninhabited or abandoned and open to the weather. If it appears that such structure would be especially unsafe in case of fire, it shall be deemed dangerous within the meaning hereof, and the local inspector may affix in a conspicuous place upon its exterior walls a notice of its dangerous condition, which shall not be removed or defaced without authority from him. Upon such notice under either of the preceding sentences, the owner, lessee or mortgagee in possession shall furnish a floor plan of such building or other structure to the chiefs of the fire and police departments of the city or town.