Adobe construction is an important part of the built heritage in the Central Region of Portugal. The protection and rehabilitation of buildings of this type is becoming of increasing interest. In-depth knowledge will enable the preservation and assessment of this ancient technique with a high potential for sustainable construction, which forms the core aspect of the current research. The rehabilitation of these structures depends on an adequate diagnosis of their pathologies. Those most frequently observed are related to structural problems, absence of structural cohesion, damage by the wooden covering structure, and the effects of damage by water effect in to the structure and walls. These are often associated with a lack of maintenance of the buildings over a long period of time or with design detailing problems, namely stemming from when reinforced concrete was introduced into the traditional adobe construction system, or again by external environmental factors. Knowledge of the process of the introduction of reinforced concrete and its motifs are also important to this study. The pathologies observed in the mixed adobe/concrete system in addition to the traditional system are related to basement moisture, corrosion of reinforced concrete, wall cracking, degradation in coverings, and single parts of the curtain wall/facade and design errors. A timely correction of pathologies will mean a significant reduction in the cost of repair works or even in saving the construction from ruin. Minimum maintenance rules applied to old buildings, associated with a proper understanding of its behavior, can increase the longevity of this vast heritage. By protecting the identity of our towns, apart from the benefit of heritage and cultural preservation, it also encourages tourism and consequently increases local development.

The debate on the rehabilitation of adobe buildings and their heritage value leads to the inadequacies that still exist in the architectural characterization and conservation status of these buildings, especially outside large urban centers. This study seeks to contribute to this debate by focusing on adobe construction techniques in Ílhavo, Portugal, during the transition phase between vernacular and the architecture of the Modern Movement. The study also seeks to contribute to developing knowledge of the evolutionary process of adobe construction, associated with the appropriation and application of the new architectural language, by focusing on the period from the 1940s to the 1960s. Identified are the major defects associated with changes in construction methods. The data are intended to support the protection of this heritage. In Portugal, increasing importance is currently attributed to modernist buildings because they are focal points for the characterization of the country's architectural history. The preservation efforts for these buildings have encountered obstacles in terms of maintaining identity, given the recent interventions that were implemented. This conflict is seen, in a comprehensive manner, in the vernacular construction of adobe. However, knowledge of historical and cultural issues could even support projects in the tourism industry by valuing and preserving heritage.

Two hundred years (1750–1950) of earthen architecture represents an important period of construction in the central region of Portugal. Earthen architecture is usually built close to the coast or to rivers and placed in sandy ground. The impact of rising damp is a general problem and efflorescences are a common cause of damage decay. This problem was studied in a building with two types of earthen construction, adobe masonry walls and formed masonry walls. The aim of this research was to characterise the conditions for the appearance and phase transitions of thénardite and mirabilite, and determine how to prevent progression of salt effects in the two types of wall to support future conservation measures. Laboratory capillarity and porosimetry tests with dolomitic air lime mortar and hygrothermal monitoring were pursued along within situtests. Visual assessment showed that the progression of salts depends on the composition of the earthen materials. To understand these differences, all crystalline solid phases were analysed by powder X-ray diffraction, and building interior hygrothermal conditions were monitored. An investigation into the influence of surface lime water painting and sacrificial mortar application on the crystallisation of sodium sulfates concluded that these also depend on the wall's composition. Data allowed us to conclude that inside the building the temperature and humidity [relative humidity (RH = 100p_w/p°_w> 70)] conditions led to the adobe breakdown by the fast conversion from thénardite to mirabilite. Therefore, contact with wet atmospheres should be avoided and interior hygrothermal conditions should be controlled. Laboratory andin situtests showed that the environmental conditions of the spaces had effects on the results. The results contribute to understanding of the salt progression and pattern of decay, as well as supporting future recommendations for building conservation, based on the identification of environmental conditions proper to their occurrence.

This work contemplates the application of non-destructive techniques, sonic and environmental vibration tests, on a set of soil-cement compressed earth blocks reinforced masonry walls, which were built in laboratory, under the project SHS-Multirisk. The present work constitutes a comparative study that aimed at verifying the reliability of the sonic test method in masonry characterization and in testing a methodology of combined tests for structural assessment. For that purpose, a numerical model of the walls was developed and calibrated with the mechanical properties that were calculated from the sonic tests data. The results of the simulation of the numerical model were compared with the results of the environmental vibration tests, which enabled to reach a correlation between the frequencies, as well as enabling the indirect sonic tests, which were performed in the vertical direction, to result in an accurate prediction of the Young modulus to be used in the numerical models.

The sustainability of cultural values of historic centers depends, to a great extent, on the balance achieved between maintaining the resident population, preventing housing abandonment, and reconciling the new functions installed in those centers. Nowadays, tourism is seen as a solution to reactivate historic centers, often neglecting the original resident population. This study analyzes two examples of urban rehabilitation in historic centers, one in Portugal and another in Brazil, respectively, Porto and Salvador da Bahia, with 1996 and 1985 UNESCO classifications, respectively. The present study analyses the interaction between the evolution of building stock, renting and tourism, focusing on aspects that result in positive and negative actions for the preservation of the built heritage of these centers, their identity and exclusion of traditional residents.