Hello, three years ago we built a brick house from Porotherm and used thermal plaster from the outside. There were small balls of polystyrene in the bagged mixture. I've been watching a weird thing for about two weeks. On the floor under the doors and windows, I have a completely soft fluffy mass, like grated polystyrene. But it's not just from the outside, but also, for example, at the same time, this "fluffy mixture" also appeared at the inner door in the living room, where the thermal plaster is not. I don't know what the "snow dust" is causing, but it scares me. What gnaws at us inside the plaster? If you have any idea, possible explanation, write to me. Thank you. Marie