It is important to investigate building performance and relate it to health and satisfaction of the occupants in order to enable sustainable and healthy buildings. This applies to both new buildings and renovation projects. Cross sectional studies and case control studies have been made on relationships between indoor environment and occupants´ health and satisfaction. However, to be able to connect the building performance and construction conditions, such as moisture conditions or material degeneration, with the indoor environment and air quality, it is necessary to look into the construction behind the surface layers, which means that the building must be taken apart. This is usually not possible because it is not allowed or economically reasonable in inhabited dwellings. This paper presents a pilot study of a project that introduces the unique possibility of investigating building performance where the buildings will be taken apart to reach behind the surface layers with the aim to develop methods for destructive testing in the main project. In the pilot study, the aim was to provide an image of the normal state of normal buildings after normal aging to assist in the design of energy-saving measures, methods for studying the performance of buildings including several leakage test, and state of the external walls and connecting parts of the building and building services and hvac systems for expanded research in the main project. Non-destructive and destructive tests were carried out in a few of houses in Malmberget in the Arctic, northern Sweden, and wall elements were taken out and tested in lab. Examples of results are damages found in attics and in wet rooms, leakage through different weaknesses in the envelope and measured U-values. The pilot study also resulted in a number of useful methods for destructive testing behind the surface layers to enable efficient destructive testing in the main project.