§ 55. Wainscoting. 1. Whenever the surface of walls, partitions or ceilings in any apartment or suite of rooms of any non-fireproof multiple dwelling is covered, sheathed or wainscoted wholly or in part after April eighteenth, nineteen hundred twenty-nine, such covering shall be backed solidly with plaster. In fireproof multiple dwellings such covering shall be backed solidly and continuously or filled with incombustible material. In the case of walls and partitions in fireproof dwellings, such backing and filling shall extend to the fireproof floor construction and in non-fireproof dwellings to the floor beams. All such backing and filling shall be fire-stopped.

2. No wood wainscoting other than fireproofed wood complying with the provisions of section fifty-eight shall be erected in any public hall, stair or shaft of any multiple dwelling.