A.   Upgrading: Existing residential units shall be upgraded whenever any of the following events occur:
      1.   Whenever wallboard, plaster or other finish material is removed which exposes wall cavities of foundations, exterior walls, floors or ceilings, these spaces shall be insulated to the degree it is practical. Where attic and crawl space areas are insulated, the space shall be ventilated as per the currently adopted UBC.
      2.   Where insulation increases the accumulation of snow, and the snow load capacity of the roof structure is exceeded, the roof members shall be upgraded to withstand the additional loads.
      3.   When access is available to foundations of existing structures, foundations shall be insulated to the standard required by the applicable Utah energy code when remodeling of the structure is initiated.
      4.   When boarded structures are renovated for reoccupancy, the structure shall be insulated to the following standards when wall, ceiling, roof or floor cavities are open or accessible: wall, R-11; ceilings and roofs, R-32; floors, R-7. Thermal resistance "R" shall have the meaning as defined in the Utah energy code.
      5.   When new habitable space is created within an existing building envelope, all such spaces shall be insulated to the current Utah energy code standards.
      6.   All replacement windows shall be double pane. Replacement glass for structures which are on the historic register or are contributory structures located within one of the city's historic districts may be determined based upon standards adopted by the city's historic landmark committee. Replacement metal windows shall have a thermal break. Single pane replacement glass may be installed on windows not designed to accept double pane glass.
      7.   All exterior door replacements shall be weather stripped.
      8.   New mechanical equipment installed shall meet a minimum of eighty percent (80%) efficiency.
      9.   Except for the other applicable requirements of this chapter, when a new addition is made to an existing residential structure, only the addition shall be made to comply with current Utah energy code standards.
   B.   Exterior Door And Window Seals:
      1.   Exterior doors and windows shall be weathertight. If broken, all panes shall be replaced with glazing in compliance with the UBC.
      2.   All doors and windows shall be properly caulked and weatherproofed. (Ord. 68-96 § 1, 1996: Ord. 55-95 § 4 (Exh. A), 1995)