• Can, in exceptional cases, be transformed by not maintaining its original appearance or configuration, including the material, form, dimensions, placement, details, stonework, finish, texture;
• Must, when it is transformed, respect or enhance the architectural expression and composition of the building and the landscape, taken individually or in relation to each other, by taking into account the original concepts or being compatible with them in form and materials, in accordance with their value.

6.1.2 Building construction and extension

• Borough by-laws must provide that on a lot marked “Institutional properties” on the Map titled “ Targeted Properties ” found at the end of the present complementary document (see Appendix J), a building may be extended beyond the building coverage ratio and beyond the height as of May 6, 2008, to provide for the construction or extension of an elevator, a stairwell, a mechanical well, a ceiling space, a vestibule or other similar space.
• Borough by-laws must set criteria requiring that the construction or extension of a building, fence, grille, wall, stairway or terrace be carried out while respecting the value of the site’s archaeology, landscape, vegetation, topography and views between a public space and the Mount Royal historic and natural district. The construction or extension project must also respect the scale, siting, cladding, cornices, openings and projections of the existing building or local context.
  
  For that purpose, the construction or extension project must:

• Take into consideration its effects on the site and on neighbouring structures so as to preserve or enhance the character of the site and its environment or be compatible with them;
• Be designed in full knowledge of the archaeological remains on the site without disturbing those that may be the subject of archaeological digs, be left in place or be highlighted, according to their documentary or educational value;
• Respect, enhance or adapt to the landscape, vegetation and topography of the site or be compatible with them, according to their importance as representative, interesting, exceptional or unique elements of the environment;
• Respect or enhance the views between a public space, the river and all exceptional natural or built elements, in accordance with their importance as characteristic or unique views and the level of attendance of the public spaces (scenic lookouts, public thoroughfares, institutions, paths) from which these views are possible.