I am not quite sure on the definition of roof area and can't find a definition. I would assume that "roof area" consists of all areas that can be seen from above the building. That includes the top of the roof parapet extending above the concrete slab that forms the ceiling (like an upstand beam, I am not 100% sure on the exact English word). Is that correct?

Or is the top of a roof parapet not included in the roof area, as it is technically the top of a wall, and not a roof?

Thanks, Jens