Mold on OSB boards in the roof after screed and plastering work

Well, someone didn’t think with the thing between their ears but with something else. Normally, there is an order in how and what you do on a construction site.

You don’t install the sanitary ceramics before tiling, but afterward.

Just as you first seal the flat roof and then pour the screed. This is top-notch botchery.

Sure, eventually it will dry out and you will be able to wipe some of it away. But it’s simply not the proper way and it creates more problems and extra work than necessary. If you’re lucky, you won’t have any consequential damage, but it’s more like 50/50. It can go well, or everything can gradually start to mold away later. OSB on the attic is not always ideal even in dry houses.

It is not only the panels but also the beams that are affected. And the amount of black mold would also prompt me to file a complaint and involve an expert. White mold can easily occur in the damp warm weather on the construction site and can be treated without problems. Black mold is somewhat more problematic, depending on the type.