What actually happens if you exceed the floor area ratio? Is there a penalty and do you have to dismantle it as soon as it is noticed?
yes. and the building authority doesn't even have to come by and check themselves, it is enough if a nasty neighbor gives a tip and triggers an inspection.
large new development area with 60 semi-detached houses and infiltration trenches on each plot)
:oops: For heaven’s sake. Will you even be able to find your own semi-detached house then, since they surely all look very similar (the same). Regarding the terrace: First clarify what is allowed. Then you can commission it directly if you don’t want to do any work on it again later. Find out the additional cost beforehand.
I will ask the developer (he will be able to answer me) how many sqm are already built or sealed with the standard 3x5m terrace including house, garage, driveway, and everything else. Then I will know how much terrace is still allowed at most.