Hygrothermal performance of structures with diffusion-open and semi-diffusion-open internal insulation systems: A literature review

Abstract

This review presents a comprehensive synthesis of current research on diffusion-open and semidiffusion-open internal insulation systems, which are often the only feasible solution for improving the energy performance of historic buildings due to legal and conservation constraints. These systems, characterized by their vapour permeability and capillary activity, enable partial inward drying and may reduce the risks of interstitial condensation and moisture-related damage in masonry structures. Relevant studies were selected using a systematic review methodology, including structured searches in scientific databases, multi-phase screening, and content analysis. The review provides a statistical overview of publication trends over the past three decades and the geographical distribution of research activity. A total of 38 studies were analyzed, comprising in-situ measurements, laboratory experiments, and numerical simulations. Special attention is given to insulation materials, modelling approaches, installation quality, and boundary and climatic conditions. Key research gaps are identified, and directions for future research are proposed to support the development of reliable and hygrothermally safe internal insulation systems suitable for application in historic buildings.This review presents a comprehensive synthesis of current research on diffusion-open and semidiffusion-open internal insulation systems, which are often the only feasible solution for improving the energy performance of historic buildings due to legal and conservation constraints. These systems, characterized by their vapour permeability and capillary activity, enable partial inward drying and may reduce the risks of interstitial condensation and moisture-related damage in masonry structures. Relevant studies were selected using a systematic review methodology, including structured searches in scientific databases, multi-phase screening, and content analysis. The review provides a statistical overview of publication trends over the past three decades and the geographical distribution of research activity. A total of 38 studies were analyzed, comprising in-situ measurements, laboratory experiments, and numerical simulations. Special attention is given to insulation materials, modelling approaches, installation quality, and boundary and climatic conditions. Key research gaps are identified, and directions for future research are proposed to support the development of reliable and hygrothermally safe internal insulation systems suitable for application in historic buildings.