For centuries the urban development of historic centres has been characterised by building transformations, notably by the construction of additionalstoreys. This practice has resulted in several deficiencies, such as inadequate hy- gienic and comfort conditions, both indoor and outdoor, and seismic vulnerability. Especially top floors show a relevant lack of performances, frequently imputed to historic buildings, in comparison with the current requirements of structural safety and thermal comfort. Referred to influential positions in the theoretic debate over the conservation of historic centres, the extensive demolition of additional top levels was proposed in recent decades. Nevertheless, several reasons suggest preserving these storeys if historical, since they are evidence of traditional building techniques and influence significantly the urban landscape. This paper analyses the construction characteristics and performances of additional storeys in historic buildings. Their recurring features (lightweight and slender structures, solutions for the protection from climate conditions) are investigated by focusing on the his- toric heritage of Palermo, where the practice of extending buildings by raising new levels was widespread both in monumental and vernacular architecture, in public and private constructions. Subsequently, the performance deficiencies of additional storeys are examined in terms of structural safety, thermal comfort and overall building energy demand, by considering both local regulations and national requirements. In conclusion, this analysis suggests focusing on historical additional storeys in order to explore the opportunities of integration between structural and energy upgrades of the architectural heritage.
|Number of pages||12|
|Publication status||Published - 2017|