Earth construction is the oldest building material known, with documented cases of the use of earth bricks since Mesopotamia around 10 000 BC. Earth construction exists throughout most of the world in different cultures, and for some countries it continues to be the main process of construction. Around 30% of the world’s population lives in buildings made from earth materials. Earthen construction is an environmentally friendly technique with a social and cultural contribution; this advantage is increased when this type of construction is applied in developing countries where the material costs counterbalance the labour costs, and where other materials and techniques are not available. Studies of material characteristics are required in order to understand the composition and specific properties of earth buildings, their heterogeneity and their degradation mechanisms. Results from two different types of adobes that represent these material characteristics in Aveiro district are shown, owing to the importance of determining and acknowledging the main characteristics of adobe buildings in order to have sufficient information to initiate conservation and rehabilitation actions.