The costs for the building component “roof” (roof cladding and sub-structure) are lower for a pitched roof regarding both the purchase price and over the lifecycle (50 years). Running expenses are also relatively constant. Only after a period of 30 years, the need of renovation arises.
The roof cladding materials can be replaced easily and without complications.
With pitched roofs, the subsequent creation of living space beneath the roof can be done without the need of elaborate and expensive annexes or attachments. By fitting skylights into a pitched roof, it will also be possible to let sunlight in and create a warm and light-filled living space under the roof.
Reference: Lebenszyklus unterschiedlicher Dachkonstruktionen, Forschungsbereich für Industriebau und interdisziplinäre Bauplanung, TU Wien, 2014 (AT)