In the new construction only aluminum window sills (14pcs) are included in the fixed price (for $680) and the surcharge to the marble window sills (brand: Nero Impala) is $2700 where the pure material value is about $1000.
A friend of mine, who built some time ago, has installed the window sills himself, unfortunately with a normal plaster facade. Therefore, now comes the question of how far to proceed differently if it is ETICS with clinker?
In addition, there is the question of whether we should use marble as offered or rather resort to granite? My feeling pulls me rather to granite, I can not justify it unfortunately. What do you think?
Never ever install exterior window sills yourself! Window sills are essential for the tightness of the facade and the professional installation often even "experts" do not want to succeed. To do it yourself would probably mean to lose the warranty on the (impact) rain tightness of the house itself. The risk would not be worth it to me.