Historic buildings and important structures can enrich a community's character while also serving as a tangible reminder of its past. They are often genuine architectural treasures. Time, however, can have adverse effects on these structures, for example poor quality design, corrosion and incompatibility of materials, severe environmental conditions, moisture infiltration, and movement and settlement near the structures. A building's lifespan can be increased with appropriate care and repair that is planned and carried out by trained personnel. In heritage structures, maintaining the original building materials is essential to extending their lifespan and preventing repetitive replacement. Specialized knowledge is needed to prevent potential material degradation and preserve architectural components in a way that allows them to perform effectively, to retain the identity of built heritage and address potential deterioration over time.

A structure's age or condition need not determine its ability to function well. Retrofitting is the process of incorporating new elements into existing constructions such as bridges, historical buildings, and so on. Rehabilitation is the process of returning a structure or an area to its previous good state, whereas retrofitting is the practise of altering a building in hindsight to improve its performance quality. Retrofitting enhances the performance of existing structures or structural components by reinforcing them using science and technology. Retrofitting a building with environmentally friendly materials has been shown to increase productivity while reducing expenses. The structure is retrofitted with consideration of its purpose of usage, performance requirements, level of safety, and required durability, with proper consideration of the simplicity of maintenance, and total economy. A comprehensive plan covering health inspection, retrofitting techniques, design of retrofitting structures, and implementation of retrofitting work is produced depending on requirements. The process starts with the examination and documentation of the health of the building. Appropriate rehabilitation or retrofitting procedures are determined based on performance analysis and inspection which is completed using multiple methods.

The aim of this Special Issue is to cover topics that are related to the degradation of structures that are important to humankind, be it a heritage building or an important structure. Furthermore, the issue covers the methods, tools, techniques, and innovations occurring within this domain. Original research and review articles are welcomed.

Potential topics include but are not limited to the following:

• Textile reinforced mortar-based retrofitting measures
• Novel retrofitting measures
• Low carbon retrofitting measures
• Retrofitting innovations in developing countries
• Green retrofitting techniques
• Light weight retrofitting measures
• Retrofitting measures for buildings under severe environmental conditions
• Scientometrics applications in retrofitting domain
• Novel materials for retrofitting
• High strength materials for novel retrofitting
• Trends in modern shear wall for retrofitting
• Advanced base isolation techniques