Terranova, a Popular Stone Imitation Cladding: Strategies and Techniques for Restoration: Strategies and techniques for restoration

At the beginning of the 20th century, the application of innovative finishes on façades became a popular phenomenon in Belgium. Decorative renders were frequently used to hide the aesthetically imperfect structure and to imitate valuable natural stone features. In order to create the appearance of French stone, ingredients such as lime, mica and crushed natural stone were added to white cement. Afterwards, the surface was scratched or scraped to shape a rough texture. As a result, a convincing ‘simili-pierre’ or ‘stone imitation’ masonry was obtained, after drawing simulated joints into the wet render layer. Today, these imitation finishes suffer in most cases from discoloration, cracks, peeling off and other damage which has completely changed the initial perception. Since knowledge is lacking concerning their composition,
properties and application techniques, many questions remain unanswered within the conservation area. As a consequence, incorrect decisions may be made during restoration campaigns, which may lead to additional damages. A remarkable example of a simili-pierre render is the former commercial product Terranova, which is the focus of the research. By means of literature studies, the exploration of historical patents, laboratory analysis of representative samples and a comparative research between similar claddings, this paper proposes legitimate solutions to revitalize the Terranova finishes. It is found that both original mortar formulas and historic application guidelines are key elements which form a fundamental contribution to restore stone imitating renderwork in a sustainable way, with respect for authenticity issues.