Recently, the author worked as a development aid worker in Peru. Lessons are drawn from this experience and from experience in the Netherlands, comparing the differences in sustainable building caused by culture, history and available techniques. Exchange of technology or technology transfer may help countries to learn from each other and achieve more sustainability. The paper uses examples drawn from the Netherlands and Peru of achieved and achievable sustainability with an eye to the functional quality, the architectural quality and the use of resources for housing. This is done for the building product, the system and the building as a whole. When comparing the situation in both countries, we find that Peru, as a LDC, sometimes has the advantage of being "retarded" in its development. Therefore, the correction of "negative" actions towards the environment can be made far more easily than in the case of a developed country. Transfer of technology (North-South & South-North) and choice of technology may be important. Based on experiences in both countries, a research programme was set up. The paper describes the investigation into the reduction of waste and residues by carrying out sustainable renovation and maintenance projects.