Editor’s note: Welcome to the sixth post in a series of blog posts developed with municipalities in mind who either have or are considering undertaking Municipal Historic Resource designation. In this post, we will introduce the concept of a “period of significance” and explain why it is important to establish as part of the designation process. You can read the previous post here.
For more information, please review the “Creating a Future” manuals available here or contact Rebecca Goodenough, Manager, Historic Places Research and Designation at firstname.lastname@example.org or 780-431-2309.
Written by: Stefan Cieslik, Heritage Conservation Adviser and Rebecca Goodenough, Manager Historic Places Research and Designation
Period of Significance
Simply put, the period of significance of a historic resource is the time frame when the place acquired its significance. The heritage value section of the Statement of Significance (SOS) articulates why the place is historically significant, such as an association with an event, person, theme, institution, style of design, etc. Each of these heritage values will have an associated time frame, which informs the period of significance.
Some associations will have start and end periods while others will still have the association today. The period may be very specific if the resource is significant for a single event, or it may span hundreds of years if it is a prehistoric cultural landscape. A period of significance is specific to a site—it is not a general era of development for a community or other reference point. Where the historic place is a building, it should never predate the date of construction.
The purpose of having a period of significance is to inform decision-making about what changes are appropriate. The character-defining elements (CDEs) listed in the SOS need to all be from within the period of significance. Non-period CDEs are then eligible for consideration for removal from the historic place. Similarly, a period of significance could extend to include multiple phases of a historic place and therefore include evolving changes to a historic place to highlight this and express later periods.
The following examples will show different periods of significance and how they influence conservation decisions. In each example, conservation decisions are in keeping with the Standards and Guidelines for the Conservation of Historic Places in Canada.
Period of significance equals date of construction
The Trend House in Calgary’s Elboya neighbourhood was constructed in 1954. It is valued for its Modernist design and association with the architectural firm Rule, Wynn and Rule. Given that significance is tied directly to the architecture and design of the structure, the period of significance dates to the year of construction. Additions or changes to the house after 1954 are not listed in the character-defining elements.
When missing mortar at the upper section of the red brick chimney was identified as a source of water infiltration, the basic hierarchy of maintenance was followed; that is, maintenance first, followed by repair rather than replacement of deteriorated elements. Only those areas with missing or deteriorated mortar were replaced, and care was taken to ensure that the new mortar materials closely matched the originals, both in terms of their appearance and performance.
Period of significance covering different eras
The Atlas Coal Mine is valued for its excellent representation of a major mining operation in the Drumheller Valley. The site is remarkable for its integrity and its association with pioneering mining practices.
Comprised of a variety of landscape elements and buildings, some of which were moved from other mines, the Atlas No. 3 includes structures erected over time to meet the evolving needs of the mining operation. Significant elements of the site include the vestiges of the mine entrance, traces of rail lines, a blacksmith shop, explosives sheds, a screening house, covered conveyor belt shafts, a wash house and three former managers’ houses. The site’s most significant structure, the No. 3 Tipple, is a unique example of an above ground coal processing structure and the last of its kind in Canada. The tipple still bears evidence of the many ‘running repairs’ that were made by the coal miners that operated it, resulting in an evocative collection of contemporary interventions that have high interpretive value.
Period of significance starts later than date of construction
The first building constructed on the Maccoy Homestead in High River was a log cabin built in 1885. The period of significance for this site starts in 1925 and continues until 1995. The reason for this is that the site is primarily valued for the contribution of women’s labour to homesteading, which began in 1925 when Ruth Maccoy and her mother Evelyn Sheppard lived and worked there. The period of significance ends in 1995 when their stewardship of the property ended after Ruth passed away. The period of significance is therefore directly linked to the time frame in which Ruth and Evelyn occupied the property.
Historic photographs indicated a washroom was built after 1954, likely in the 1980s during Ruth Maccoy’s later years. The earlier open porch configuration, including original drop siding and ceiling, was confirmed once the floor structure was dismantled. That evidence supported a new proposal to restore the earlier appearance of Ruth Maccoy’s home rather than reinstate the washroom. The rationale for restoration included the arguments that the open porch existed for most of the site’s history, and that the house with open porch better represents the rustic living conditions at the site during Ruth Maccoy’s life there.
Period of significance continuing until today
In some cases, the period of significance for a historic place does not have an end date. This is true for the Nikka Yuko Centennial Garden in Lethbridge. Constructed in 1966 for Canada’s centennial, the garden retains its original design characteristics and remains a ceremonial garden strongly associated with Alberta’s Japanese community. As the garden continues this function, nothing has occurred that would disrupt the period of significance between 1966 and the present.
The next blog in this series will explain Statements of Integrity and how this assessment helps to understand the physical condition of places under consideration for designation.