More detailed guidelines are set out in the Standards and Guidelines for the Conservation of Historic Places in Canada (10mb). These guidelines apply to Municipal Historic Resources, in particular as alterations are being proposed to the structure.
- Compatible Uses
Wherever possible, the uses proposed for a Municipal Historic Resource shall be compatible with the existing building such that only minimal changes are required to the building. The use of a Municipal Historic Resource for its original purpose is desirable.
- Original Character
The original distinctive qualities and character of the Municipal Historic Resource shall not be destroyed. The removal or alteration of any historical materials or features shall be avoided whenever possible.
- The Historic Period
The Municipal Historic Resource should be recognized as a product of its own time. Alterations which are not based on historical fact or which recreate an earlier or a later appearance shall be discouraged.
- Witness to Change
Changes to the Municipal Historic Resource may have occurred over time. These alterations are evidence of the history and development of the Building. Because this evolution may have acquired significance in its own right, alterations to the original Building should be recognized and respected where indicated.
- Style and Craftsmanship
Distinctive stylistic features and examples of skilled craftsmanship which have been designated by the Municipal Historic Resource Bylaw shall be preserved and treated sensitively.
- Repair and Replacement
Deteriorated architectural features shall be repaired rather than replaced whenever possible. Where replacement is necessary, the new material should match the original as to composition, colour, texture, design. The repair or replacement of architectural features shall be based on a sound knowledge of the original characteristics of the feature. Such knowledge shall be based on historical or pictorial evidence and not upon conjecture.
In all cases, surface cleaning shall be undertaken with the gentlest means available. Sandblasting in particular, but also other cleaning methods, damage historic buildings and should not be undertaken without thorough testing prior to use on a building. Sandblasting is not recommended on brick, stone or wood. In all instances, it should be ascertained that a building exterior is really in need of cleaning prior to undertaking the work.
- Reversibility of Intervention
When the introduction of new elements or materials are necessary to stabilize or preserve a municipally designated historic resource, alteration shall be undertaken such that the new materials, should they fail, may be removed at a later date without damage to the original fabric of the Municipal Historic Resource. Where this is not possible (i.e. use of epoxy) only those methods and materials which have been thoroughly tested and found satisfactory in situ, shall be used.
Prior to undertaking any alterations, particularly in cases where alterations may threaten the building fabric (underpinning, moving structures), the applicant shall compile a complete record of the architectural features of the Municipal Historic Resource. Measured drawings and photographs of details may prove invaluable if major features are damaged or lost during the subsequent repair work.
- Original Construction Details
In some historic structures, poor construction details or inappropriate materials resulted in rapid deterioration of certain building elements. In these instances, accurate reconstruction of the original detail will inevitably result in the failure of the element. Therefore, reconstruction should be undertaken in such a fashion as to duplicate the original appearance as closely as possible while using details based on sound construction practice.
At no time should the life and safety of occupants of a Municipal Historic Resource be deemed of lesser importance than the preservation of the original fabric of the Municipal Historic Resource. The required life and safety standards are those required by the current Alberta Building Code.
However, notwithstanding these Code requirements, where the essential character of the structure is threatened by changes for Code reasons, every effort shall be made to achieve an equivalent safety standard by alternate means so as to minimize the impact on the historic fabric.
Prior to undertaking any improvements, a schedule of alterations should be prepared. This schedule should include phasing of alterations where necessary due to program or budget restrictions. The type and timing of both short and long term maintenance work shall also be included.
As a general rule signs should be limited to signs which were originally present on the building. In instances where new uses or interpretive functions dictate the use of additional signs, these new elements should be integrated into the general design of the project. The size, typeface, graphics, and materials should be chosen to suit the period of the Municipal Historic Resource wherever possible. Avoid installing new signs such that the repair, replacement or removal of the signs damages the original fabric of the structure.
- Alterations and Additions to Historic Resources
Contemporary design for alterations and additions to existing Historic Resources shall not be discouraged when such alterations and additions do not diminish the overall historic character of the resource and such design is compatible with the size, scale, colour, material and character of the resource, neighbourhood or environment.