Architecture Specialty Group Morning Session: Lime Grouts, Environmental Control and Site Management

The second group of presentations in the Architecture Specialty Group’s morning session covered a range of topics. Victoria Pingarron Alvarez of the University of Pennsylvania presented “Performance Analysis of Hydraulic Lime Grouts for Masonry Repair.” Ms. Alvarez described research carried out in 2005 and updated with current research to evaluate low-strength grouts used for adhesion. Moderately hydraulic lime grouts were formulated with different concentrations of El Rey Superior 200, an acrylic polymer emulsion, and subjected to tests of their mechanical and physical properties. A mix of 2 parts lime, 1 part fine mason’s sand, 1 part ceramic microsphere filler and 10% solution of acrylic emulsion in water yielded a grout with low shrinkage, moderate resistance to frost and compatible tensile and compressive strengths to historic masonry. Future research related to Ms. Alvarez’s work may address the suitability of test standards, as all of the test standards used in the evaluation of the lime grouts were modified in some way.

Ben Haavik and John Childs, both of Historic New England, gave the presentation “Revisiting Realty: A Changing Approach to Environmental Control in Historic House Museums at Historic New England.” Historic New England manages over 120 buildings and 1200 acres at 36 sites, and its collections include over 50,000 objects in its house museums as well as another 70,000 objects in storage. The introduction of environmental control systems at several Historic New England house museums in the 1990s quickly resulted in problems that are currently being addressed with a revised approach to environmental control. Two case studies were used to demonstrate Historic New England’s new approach to environmental control, which is a simplified approach applied incrementally. It includes a wider acceptable range of relative humidity, a monitoring program, humidistatic heating and simplification of equipment.

The final presentation of the morning by Avigail Charnov of Historic Resources Group was “A Review of 100 Years of Site Management.” The presentation, co-authored with Jake Barrow of Cornerstones Community Partnership and subtitled “Conservation of Earthen Sites in the American Southwest,” examined the creation of national monuments and parks in the southwest and the development of conservation efforts at these sites. While early conservation treatments were not well documented and were often undertaken in a trial and error fashion, a fundamental shift in conservation practices occurred in the 1970s. This shift incorporated laboratory material analysis, increased levels of documentation, monitoring of conditions, critical evaluation of treatments and a collaborative team approach.