The period from 1946 to 1980 was the most intensive in residential building construction in Slovenia. Thus, 61% of all existing residential buildings are from that time and 63% of dwellings built in that time are located in urban, multi-storey buildings. Roughly half of total number of dwellings in urban areas has floor space in the range of 45 to 74 m². Typical residential buildings in Slovenia have either masonry or reinforcement concrete structure. Envelopes of recently erected buildings are insulated what is not usual case for buildings erected between 1946 and 1980. Residents of dwellings with large open air balconies and terraces tend to enlarge dwellings by closing them what usually harms architectural appearance of envelope. Interventions in envelopes in many cases may bring the additional strength and earthquake resistance to entire building. In general, the importance of envelope for aesthetic, structural and functional aspects of residential building should not be neglected.