Why do I get bad shadows from my lightmaps?

Jesus i’m so stupid, i didn’t saw the floating polygons, i can’t even explain why i didn’t saw them…
I have a older version of this building, where the windows are still attached to the main mesh. So basically i need just to detach the windows “in a clean way” this time… and the lighting should’t be longer a problem ?

what can i say, stupid i :slight_smile: but many thanx! this wont hapend a second time to me…
I’m going to sleep now but i will try it right at the morning…