Heritage Preservation Best Practices

The Conservation Decision-making Process includes a step-by-step guide to understanding, planning, and intervening on a historic place as part of an ongoing cycle of use, maintenance, repair, and adaptation. 

The Conservation Treatments introduces and explains the three conservation treatments: preservation, rehabilitation, and restoration.

Preservation: Preservation involves protecting, maintaining and stabilizing the existing form, material and integrity of a historic place or individual component. Preservation can include both short-term and interim measures to protect or stabilize the place, as well as long-term actions to stave off deterioration or prevent damage. This will keep the place serviceable through routine maintenance and small repairs, rather than inoperable during intrusive interventions, extensive replacement, and new construction.

Rehabilitation: Rehabilitation involves the sensitive adaptation of a historic place or individual component for a continuing or compatible contemporary use. Rehabilitation can include replacing missing historic features.

Restoration: Restoration involves accurately revealing, recovering, or representing the state of a historic place or individual component as it appeared at a particular period in its history, while protecting its heritage value. Restoration may include removing non character-defining features from other periods in its history and recreating missing features from the restoration period. Restoration must be based on clear evidence and detailed knowledge of the earlier forms and materials being recovered.

The Standards for the Conservation of Historic Places in Canada introduces and explains the fourteen standards, with interpretations and illustrated examples. 

Standards for Preservation, Rehabilitation, and Restoration

• Conserve the heritage value of a historic place. Do not remove, replace or substantially alter its intact or repairable character- defining elements. Do not move a part of a historic place if its current location is a character-defining element.
• Conserve changes to a historic place that, over time, have become character-defining elements in their own right.
• Conserve heritage value by adopting an approach calling for minimal intervention.
• Recognize each historic place as a physical record of its time, place and use. Do not create a false sense of historical development by adding elements from other historic places or other properties, or by combining features of the same property that never coexisted.
• Find a use for a historic place that requires minimal or no change to its character-defining elements.
• Protect and, if necessary, stabilize a historic place until any subsequent intervention is undertaken. Protect and preserve archaeological resources in place. Where there is potential for disturbing archaeological resources, take mitigation measures to limit damage and loss of information.
• Evaluate the existing condition of character-defining elements to determine the appropriate intervention needed. Use the gentlest means possible for any intervention. Respect heritage value when undertaking an intervention. 
• Maintain character-defining elements on an ongoing basis. Repair character-defining elements by reinforcing their materials using recognized conservation methods. Replace in kind any extensively deteriorated or missing parts of character-defining elements, where there are surviving prototypes.
• Make any intervention needed to preserve character-defining elements physically and visually compatible with the historic place and identifiable on close inspection. Document any intervention for  future reference.

Additional Standards Relating to Rehabilitation

• Repair rather than replace character-defining elements. Where character-defining elements are too severely deteriorated to repair, and where sufficient physical evidence exists, replace them with new elements that match the forms, materials and detailing of sound versions of the same elements. Where there is insufficient physical evidence, make the form, material and detailing of the new elements compatible with the character of the historic place.
• Conserve the heritage value and character-defining elements when creating any new additions to a historic place or any related new construction. Make the new work physically and visually compatible with, subordinate to, and distinguishable from the historic place.
• Create any new additions or related new construction so that the essential form and integrity of a historic place will not be impaired if the new work is removed in the future.

Additional Standards Relating to Restoration

• Repair rather than replace character-defining elements from the restoration period. Where character-defining elements are too severely deteriorated to repair and where sufficient physical evidence exists, replace them with new elements that match the forms, materials, and detailing of sound versions of the same elements.
• Replace missing features from the restoration period with new features whose forms, materials, and detailing are based on sufficient physical, documentary, and/or oral evidence.

The Guidelines for the Conservation of Historic Places in Canada form the bulk of the document. The Guidelines are intended to assist in applying the Standards and determining whether their intent has been met in the context of specific interventions to historic places.

There are five principal sections in Chapter 4 regarding the Guidelines.

4.1 Cultural landscapes

4.2 Archaeological sites

4.3 Buildings

4.4 Engineering works. 

4.5 Materials.

Look up Conservation Guidelines for 4.3 Buildings, and 4.5 Materials

The Boston Mills Press published Well-Preserved: The Ontario Heritage Foundation’s Manual of Principles and Practice for Architectural Conservation. The publication, edited by Mark Fram, provides an introduction and practical guide to the restoration and rehabilitation of our architectural heritage.

• Introduction
• The inheritance
  
• Careful conservation
• Good practice, Assessment, Archaeology, Environment
• Design, Project management
• Building site, Structural systems
• Exterior features
• Interior features, Utilities, Energy conservation, New construction, Maintenance
• Ways and means
• Appendices, Bibliography, Illustrations, Index

Preservation Briefs provide information on preserving, rehabilitating, and restoring historic buildings. These publications help historic building owners recognize and resolve common problems before work. The briefs recommend methods and approaches for rehabilitating historic buildings that are consistent with their historic character.

The Briefs are technical and topic-specific.  They include many common topics, such as:

• Repointing Mortar Joints;
• Roofing;
• Repairing Historic Windows;
• Exterior Paint Problems on Historic Wood;
• Rehabilitating Historic Storefronts;
• Exterior Additions to Historic Buildings;
• Substitute Materials on Historic Building Exteriors;
• Preserving Historic Wood Porches, etc.

There are more than 50 Preservation Briefs.

Preservation Tech Notes are case studies in historic preservation. They provide practical information on traditional practices and innovative techniques for successfully maintaining and preserving cultural resources.

Explore the Tech Notes:

• Doors
• Exterior Woodwork
• Finishes
• Historic Glass
• Historic Interior Spaces
• Masonry
• Mechanical Systems
• Metals
• Museum Collections
• Site
• Temporary Protection
• Windows