Section 25-311. Maintenance and repair of improvements

a. Every person in
  charge of an improvement on a landmark site or in an  historic  district
  shall  keep  in  good  repair  (1)  all of the exterior portions of such
  improvement and (2) all interior  portions  thereof  which,  if  not  so
  maintained,  may  cause  or  tend to cause the exterior portions of such
  improvement to deteriorate, decay or become damaged or otherwise to fall
  into a state of disrepair.
    b. Every person in charge of an  improvement  containing  an  interior
  landmark  shall  keep  in  good repair (1) all portions of such interior
  landmark and (2) all other portions of the improvement which, if not  so
  maintained,  may  cause or tend to cause the interior landmark contained
  in such improvement to deteriorate, decay or become damaged or otherwise
  fall into a state of disrepair.
    c. Every person in charge of a scenic  landmark  shall  keep  in  good
  repair all portions thereof.
    d.  The  provisions  of this section shall be in addition to all other
  provisions of law requiring any such improvement  to  be  kept  in  good
  repair.