I now removed the buildings and put the bulding lot numbers instead. It seems that not all zoom levels are rendered yet, but you can already have a look!

Okay, so tagging them as "construction" is not enough it seems. How do I hide the buildings? I could put the building lots (Bauplätze) there, this is something which is marked by corner stones even now. See http://www.gbstern.at/projekte-und-aktivitaeten/stadtteilmanagement-sonnwendviertel/projekte-im-sonnwendviertel/
Also the foot paths are actually there, so they could stay, right?