Pennsylvania Statutes Title 53 P.S. Municipal and Quasi-Municipal Corporations § 15070. Certain tenement houses to be fireproof

All such tenement houses, more than four stories in height, which shall hereafter be erected, altered or constructed, shall be made fireproof throughout:  Provided, however, That this section shall not preclude the use of wooden floor boards and sleepers or beams to which to fasten the same, which, however, shall be imbedded to their top surface in incombustible material.