§ 11. Dwellings damaged or moved. 1. If a multiple dwelling be damaged by fire or other cause to the extent of two-thirds or more of its value at the time of such damage exclusive of the value of the foundation, such dwelling shall not be repaired or rebuilt except in conformity with the provisions of this chapter relative to dwellings erected after April eighteenth, nineteen hundred twenty-nine.

2. If any non-fireproof stair in any multiple dwelling be damaged by fire or other cause to such extent that such stair or the first flight thereof above the entrance story is required to be rebuilt, such stair to the extent that it is required to be rebuilt shall be fire-retarded throughout.

3. If any dwelling be moved from one lot to another, such dwelling shall thereupon be made to conform to all the provisions of this chapter relative to light, ventilation, fire protection and egress of a dwelling erected after April eighteenth, nineteen hundred twenty-nine, but no frame building of any kind whatsoever shall be moved so as to be placed upon the same lot with any multiple dwelling, nor shall any multiple dwelling be moved so as to be placed upon the same lot with any frame building.