Track 4: This New World: Preservation technology and emerging issues within our historic buildings and built landscapes
4 - Perry’s Victory and International Peace Memorial: Lessons Learned from a Decade of Restoration
Tuesday, September 25
10:30 AM - 12:00 PM
Wiss, Janney, Elstner Associates, Inc.
The Perry Memorial is a 350-foot-tall Doric column constructed in 1913–1915 and located on an island in Lake Erie. It memorializes both the War of 1812 Battle of Lake Erie and the subsequent enduring peace between the United States and Canada. Constructed of granite masonry against which structural concrete was poured, over the decades the memorial has suffered from ill-conceived maintenance and misapplication of new technology, exacerbated by the logistics of working on a relatively inaccessible island location. Over the past decade, WJE has completed a series of projects on behalf of the National Park Service to restore the memorial.
The first project addressed the structural deterioration of the top observation deck. Waterproofing installed in a prior project was unsuccessful, and water infiltration into the cantilevered concrete and granite structure had resulted in severe freeze-thaw damage. The project included replacement of structural concrete, installation of new waterproofing, and repair of granite. An innovative suspended shoring assembly was constructed atop the memorial, allowing the work to proceed without the need for a shoring tower extending 300 feet from grade. Another key component of the project was the introduction of new davit sockets and cable ports, to allow for easy rigging of the memorial for access via suspended scaffolding, for the subsequent phases of work and ongoing inspection and maintenance.
The most recent project, completed in 2018, has involved removal of silicone sealant from all masonry joints and repointing with mortar. Elastomeric sealant was first used on the memorial in the 1960s, and new silicone was installed in all joints in the early 1980s. The intent behind the use of the “new technology” of this sealant was to make the masonry completely watertight. Achieving a perfect installation of sealant proved impossible, and small breaches allowed moisture to penetrate into the construction. Where water tried to exit through joints, the sealant debonded, and the system began to unravel. As part of the current project, the granite surfaces were carefully cleaned with a microabrasive system to remove a heavy build-up of efflorescence. By replacing the impermeable elastomeric sealant with traditional pointing mortar, the ability of the memorial to manage moisture migration should be re-established, avoiding the concentrated water infiltration and exfiltration that previously resulted in heavy staining. A key component of the project was the use of third-party quality control inspection to ensure that the mortar was installed as specified and achieved a good bond to the substrate.
Across these projects, a key point of decision has been to determine when a new technology (such as microabrasive treatment) should be applied to the memorial, and when the use of new technology from years past (such as elastomeric sealant in granite joints) should be discontinued.
- Upon completion particpants will be able to understand the benefits and limitations of elastomeric sealant in masonry.
- Upon completion particpants will be able to understand the use of microabrasive techniques for masonry cleaning
- Upon completion particpants will be able to understand the importance of providing reasonable means of access for ongoing maintenance of historic structures
- Upon completion particpants will be able to understand the importance of quality control procedures during construction for implementation of durable repairs.