Track 1: Decline vs. Revival: Tempering the Impulse to Tear Down and Start Over
Thin-Stone Veneers: When Performance, Preservation, and Public Safety Are at Odds
Tuesday, September 25
8:30 AM - 10:00 AM
Location: BNCC- 101AH
Obsolete building technology is a common challenge for aging buildings, especially when the preservation of those technologies and life safety requirements are seemingly at odds. Historic facades are increasingly under scrutiny as potential sources of serious overhead hazards, and fatality incidents due to failures – even in those areas with façade inspection legislation in place, continue to occur.
Midcentury modern buildings added extraordinary complexity to façade systems with the introduction of new wartime materials and untested technologies. Even today, the building envelope is the most experimental building system, continually tweaking assemblies to push buildings taller, lighter, faster, and cheaper. Thin-stone veneer, a façade system of stone panels typically less than 2-inches thick, were introduced in the late 1940s; this system reduced weight and cost while playing into the mid-century aesthetic of sleek surfaces and planar architecture.
Widely adopted and still in use today, thin-stone veneers were not without high profile and well published failures. Poor understanding of stone behavior in thin panels has been a key issue, as well as failures of panel anchorage systems, both resulting in catastrophic collapse of thin-stone veneers.
Using several case studies, including the Dental Branch Building, a 1951 thin-stone veneer designed by architects MacKie and Kamrath, this presentation will discuss key issues relating to the “hows” and “whys” of failures of historic thin-stone veneers. The impact of detailing, stone behavior, climate, and installation will be covered, in addition to the impact of both changing building codes and our evolving understanding of how façades behave. This presentation will further review the conflicts between preservation of an obsolete but technologically important system and modern requirements for life safety of building enclosures.
- Understand the technological development of thin-stone veneers as a facade system
- Recognize failure modes and distress conditions related to material performance and installation issues for stone panel facades
- Select non-destructive testing methodologies appropriate for assessing hidden distress conditions for thin-stone veneers
- Identify when failures and distress conditions elevate to life-safety issues and how to address these failures to restore performance