Drywall storage room / hobby room, tips

Am I right in assuming that I can't go wrong with a rough construction width of 760mm and that this keeps all options open for a "standard width" door?

Yep, that's right. With that, you can install a standard door.

But also consider the practical side: if you want to move somewhat bulky items in and out through this door opening, I find the 70 cm doors quite narrow. I wouldn’t go below 80 cm (aiming for an 885 mm raw construction opening) unless necessary – the price difference for the frames and doors themselves is minimal.

But also consider the practical side: if you want to move somewhat bulky items in and out through this doorway, I find the 70 cm doors quite narrow. I wouldn’t go below 80 cm (meaning aiming for an 885 mm rough opening) unless necessary – the price difference for the frames and doors themselves is minimal.

That’s the only thing I had considered as well. Since it is solely a storage room or pantry, there are only tall shelves, a freezer/refrigerator, and a table in there – so everything fits quite well crosswise/vertically etc. The sofa, etc., is on the other side of the room, which is not accessible through this door.

With the narrower door I gain more floor space, especially in the storage room, which is very important to me.

When it comes to the cladding, it then makes sense to start with the simple cladding of gypsum board and then put OSB boards on top, correct?

Conversely - first OSB boards, then put GK on top.

Are any special profiles still needed for the floor/ceiling -- wall transition?

In the end, I put the UW profiles 50mm, the CW profiles 50mm, the door lintel profile 50mm, as well as a sealing tape and the appropriate screws for this into the shopping cart. With that, I can build the matching rectangular frame all around, right?