Alternative Backing Methods for Lifted Mosaics

The conservation of these lifted mosaics requires placing the mosaics on new backings that can support their weight with minimum deformation, while holding the tesserae in place. Unfortunately, available low-cost backing methods, like reinforced concrete, can introduce rebar corrosion and potentially deleterious materials like salts. Lightweight and more durable backing methods such as honeycomb aluminum panels, which are currently the standard in the field, can be prohibitively expensive. Thus, the backing or re-backing of thousands of lifted mosaics is a major conservation challenge in the region, where resources are scarce and costly conservation treatments are reserved for only the most exceptional artifacts. The result is that lifted mosaics, especially those in storage, continue to deteriorate at a rapid rate.

The Conservation Institute is addressing this situation by investigating alternative backing methods that are (a) prepared using locally available materials, (b) cost effective, (c) durable (noncorrosive, low salt content, etc.), (d) reversible, (e) rigid enough with respect to size of mosaics (no warping and sagging), (f) lightweight, and (g) constructed in a time-efficient manner. While this study targets mainly mosaics stored without backings, the new backing methods being developed will also be useful for mosaics on display or for those which require the replacement of existing deteriorated or inappropriate supports.

• identification of hydraulic lime mortar types and formulations that can be used as backing material (mortar testing)
• performance evaluation of low-cost panels in the backing system (mid-scale and large-scale mock-up testing)
• development of a finite-element computer model of the backing system
• production of user-friendly design charts and/or tables using finite-element computer modeling of the backing systems to guide practitioners in choosing the best backing method for their mosaics
• implementation of the developed backing method using locally available materials in selected MOSAIKON countries to validate the reliability of the computer model

Conservation Institute: Beril Biçer-Şimşir, Project Manager; Eric Borlatto, Traci Lucero, Gary Mattison, Iago Pozo, Arezoo Razavizadeh, Tina Segler, Anjo Weichbrodt

Advisors: Jeanne Marie Teutonico, Antoine Wilmering, Thomas Roby, Leslie Friedman, Jerry Podany, Eduardo Sanchez

Consultant: Dr. Ertugrul Taciroglu, Civil and Environmental Engineering department, UCLA