ᐅ Move in first – then do plastering, painting, and installing floor coverings.

We had to do it in the attic because the drywall contractors seriously let us down schedule-wise with the roof extension. And let me tell you, it was a complete mess. We had wisely not set up the furniture yet and stored it in the garage. Only the bed was placed there with a few bags of clothes, which we carefully covered with plastic during the day. Still, everything ended up dusty. When we moved in, some walls upstairs didn’t even have drywall installed yet, so we had to put up the drywall ourselves, then fill, sand, prime, and paint—while the electricians and heating installers were coming in between (they couldn’t get up there earlier because of the drywall contractors’ delay). A real nightmare.

And because two years ago, due to time pressure (we were afraid the furniture would get moldy in the damp garage), we only did it in one go, this “summer holiday” we’ll mostly clear out the attic again and do the filling, sanding, and painting once more. The walls look really bad up there in places. It’s going to be quite unpleasant... hopefully, a dust barrier door will keep most of it from spreading to the lower floors.

Long story short: You can do it, but it’s going to suck.

Yes, they hold up @Winniefred
I also reworked two rooms in the attic, presumably to Q3 standard, because the results were quite... mixed. But there were already standard doors installed and a dust protection door in front. That’s sufficient. A very thin layer of dust still settles in the hallway outside, though, if you do a lot of sanding. Fortunately, I only had to sand very little in the end. Still, it was better that we didn’t have any furniture, pictures, or anything else standing in the upstairs hallway.

That’s good to know, thanks.

I could still slap the drywall installers, seriously. The trouble they can cause when they don’t finish their work on time is unbelievable. But well, it is what it is.

Well, due to time constraints, we also finished the two rooms after moving in. At that point, only priming, wallpapering, and flooring were planned. That I had to do some additional filling later was not foreseeable at first.

It’s very important that you take off your shoes and clothes INSIDE the room. If you run back and forth across the house three times for a spatula or a tape measure, you'll spread the fine dust everywhere.

From what I’ve seen at the neighbors’ place, I definitely wouldn’t want to do it. The dirt and dust coming from unprimed screed is a disaster. They completely mismanaged the timing during the interior work because they planned everything themselves or with friends and family. The large bathroom still isn’t finished. And their rental agreement ended at the end of December...

Yes, that’s all clear. We did a lot of the work ourselves, and otherwise, most things went really well. This particular issue was definitely caused by outside fault. Unfortunately, we have to deal with it now. I would never have done this voluntarily. If it affected my entire apartment/house, I would rather stay two weeks in a holiday rental than go through this hassle. In our case, it was “only” the attic, so just the master bedroom and a secondary bathroom were affected.

Our attic is basically finished. However, the ceilings especially don’t look nice, and over time it has become annoying. So we decided to take it on again and will sleep in the living room during that time. A friend who is a tradesman and my brother will help us, so I hope we can get it done in 3-4 days.

We definitely need a good dust protection door because we kept the original attic door (from 1921) and only restored it, so it certainly won’t hold back much dust.

Well, for us it was a new build and two of the three bedrooms. That was fine. Now they are occupied and all the trouble is forgotten!

I had the ceiling in the whole house done with spray plaster filler with a 1mm (0.04 inch) grain size. That could only be done before moving in, it was a huge mess.