Last joint chipboard floor (10 cm)

[NiBaBaD]

It's just about placing the 10cm piece just like all the other boards. You're going to have 45mm studs, then 11 OSB and 12 gypsum, then a 12mm baseboard, I assume? Then you're up to 80mm. It doesn't seem likely that you would load the last 20mm of the piece so much that it would sag. That will hold every day of the week

But you're suggesting that I should saw 10cm on a number of floor particle boards? I'm pondering if you place a 95x28 imsom kottling between the wall and out so that it becomes tight and gets some support. You'll get a 1-2 cm gap, but once the parquet is laid and the baseboard is nailed, it won't be visible. It might be amateurish, but it pains me to saw a small strip on 4 particle boards.

 

[PatrikJo]

There are many ways to do that.
One way is to finish laying the floor. Sure, it feels a bit silly to waste a board for a decimeter, but you can't win every time. If you had cut the first board a bit, you wouldn't even have reflected on this.
Another way is to cut all four pieces from the same board. You do lose the grooving on the boards, but since it's only a few centimeters that will actually be used as flooring, it shouldn't make any difference. Maybe you can put an extra piece under each joint so you have something to glue and screw into?
Otherwise, you've received several suggestions on how to build up the hole. If you do that, you will probably regret it when laying the real floor on the chipboard later.