Track 3: DELIVERY – INTERVENING INTO HISTORIC PLACES / Volet 3 : Réalisation – Intervenir dans les lieux historiques

Improvements to Freeze-Thaw Resistance of Historic Mortars

Saturday, October 14
10:45 AM - 12:15 PM

While the long-term destructive potential of liquid water in masonry assemblies is well known, the potential for disruption of saturated mortars exposed to freezing conditions can represent a more challenging and more immediate problem. High permeability mortars, valued in historic preservation work, also have the potential to become rapidly saturated. Projecting elements such as buttress caps, water tables and copings are particularly vulnerable. The problem is exacerbated in situations such as pavements and stairways, where water ponding and saturation prior to freezing may be further complicated by the presence of deicing salts.

Early freeze thaw failures of air-entrained Type O portland cement-lime masonry mortar on projecting elements at the East Block on Parliament Hill in Ottawa led to initiation of a testing program aimed at evaluating a potential amendment for improving freeze-thaw resistance. Early freeze-thaw failures of several natural cement pavement mortars at the Foley Courthouse in Albany, NY led to a second study, examining a variety of historic mortars in pavement joints, including natural cement, natural hydraulic lime and portland cement-lime mortars.

The presentation reviews the testing programs and methods, the materials evaluated, the results of testing, and the mortar amendments determined to be most effective in improving freeze-thaw resistance while maintaining high moisture vapor permeability. Saturation coefficient reduction was determined to be the most effective strategy for improving performance in salt-scaling resistance, as determined by ASTM C672 testing.

Learning Objectives:

Michael Edison

Edison Coatings Inc.

Michael Edison, Chemical Engineer and President of Edison Coatings, has been working in product development, formulation and technical support for 44 years. He holds a degree in Chemical Engineering from Polytechnic University (NYU) and and MBA from the University of New Haven. He is Vice President of the Society for the Preservation of Historic Cements, Inc., and Task Group Chair of ASTM C1.10.01 on Natural Cement.


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Chad Lausberg

Senior Chemical Engineer
Edison Coatings Inc.

Chad Lausberg, Senior Chemical Engineer, has worked in various technical functions at Edison Coatings Inc. for over 10 years. He currently works primarily in technical and field support services, including product development and optimization, project consulting, and customer outreach. He holds a degree in Chemical Engineering from Penn State University.


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David Edgar

David Edgar is a British conservator, stone carver and restoration stonemason with 15 years experience working on heritage buildings and monuments - most recently the West Block Rehabilitation Project at Parliament Hill, Ottawa.
David has lectured for the Ontario Association of Architects, The Canadian Association for Conservation and the APT, as well as the Universities
of Carleton and McGill. David has recently started his own company, based near Ottawa: David Edgar Conservation Ltd.


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Improvements to Freeze-Thaw Resistance of Historic Mortars

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