Same topic with us, we got the screed laid just before Christmas, and the screed layer messed up accordingly. We also wanted to get to it and clean, but I have now reconsidered and am waiting until Monday when everyone is working again at the main contractor. I will then ask whether we are allowed/can clean before handover without affecting the warranty. Honestly, I am not in the mood to do their job, only for a later externally caused error to be blamed on us. As the saying goes, the executing company has to protect its trade? Or does that not apply to main contractors or prefabricated houses?