The bigger part of multi-storey apartment buildings in Denmark from the period 1960-80 were fitted with flat roofs covered with asphalt felt. The construction of these roofs and the quality of the asphalt felt used were in general not adequately tested prior to be used, and therefore the majority of them had to be renovated after a shorter period. In stead of just replacing the original roof with a new one, it is now a days rather common to ad an extra storey where that is possible according to local planning. The reason is as a rule based on economical benefits, but very often this extra storey also gives a lift in the architectural appearance of the building. This case has been chosen because the combination of the two seems to be fulfilled.