Glass-fibre meshes for reinforcement of wall covering systems: applications, requirements, technical evaluation

Abstract

Glass-fibre meshes have been utilised for reinforcing various types of wall coverings, primarily to improve: cracking behaviour; impact resistance, and system cohesion/adhesion. These applications have increased with the continuous introduction of innovative systems in the market, which demand a wide array of properties. Examples include: renders and plasters based on cement, cement-lime, or gypsum; resin-based external wall coverings; External Thermal Insulation Composite Systems (ETICS); thermal insulation composite systems with thermal insulation mortars; panels for cladding. Different materials to be reinforced and different contributions for their performance, need specific requirements of the glass-fibre mesh, concerning, for example, mesh size, mass per unit area, tensile resistance, elongation at rupture, resistance to alkalis, durability and fire reaction. It is crucial to ensure the characteristics and durability that enable the reinforced covering systems to achieve the desired performance. For many years, Laboratório Nacional de Engenharia Civil (LNEC) has defined the requirements for glass-fibre meshes to be used in the reinforcement of various wall coverings and national technical agreements (Documentos de Homologação) have been issued accordingly. More recently, the European Organisation for Technical Assessment (EOTA) has published a European Assessment Document (EAD) titled “Glass-Fibre Meshes for Reinforcement of Cementitious or Cement-Based Renderings”, which covers part of the application field of these meshes and allows the issuance of European Technical Assessments (ETA). The article aims to analyse the requirements, and the available methodologies for the technical evaluation of meshes used in the reinforcement of wall coverings. Furthermore, it discusses future perspectives concerning the use of these elements.