• • Must be preserved or restored or, if necessary, replaced in keeping with their original form and appearance when they are visible from a public thoroughfare adjacent to the lot;
  • Are governed by rules and criteria when they are restored or replaced except for an architectural characteristic of a large site of institutional character that must be regulated by specific criteria;
  • May, in exceptional cases, be altered based on an evaluation conducted according to specific criteria without maintaining their original appearance or configuration;
  • Must, when they are altered, respect or enhance the architectural expression or composition while taking into account the original concepts or be compatible with them, according to their value.
• Borough by-laws must require that a fence, grille or wall of architectural interest, a cluster or row of trees located on a large site of institutional character or in the front yard of a building included in an area of exceptional value, or a building of heritage and architectural interest, is covered by protective measures.

6.2.2 Building construction or extension

• Borough by-laws must set criteria to require that construction or extension projects for buildings located on a large site of institutional character, or in an area of exceptional heritage value, or on the site of a building of heritage and architectural interest included on the lists presented in Part II of the Master Plan be carried out so as to ensure their integration into the surrounding environment and the overall character of the area when they are visible from a public thoroughfare bordering the site.
  
  Borough by-laws may establish rules or criteria to require that extension or construction projects for buildings located in an area of significant value be carried out so as to ensure their integration into the surrounding environment and the overall character of the area, when they are visible from a public thoroughfare bordering the site.
  
  For that purpose, an extension project must:
  
  
• Consider the character of the building to be extended, including the type, expression and architectural characteristics such as the cladding, cornices and openings;
• Take into account the extensions made to similar buildings with respect to the size, position in relation to the main building and the architectural characteristics typical of such extensions;