Fiberboard 13mm to be or not to be?

[mxjolle]

Hello!

We have a birdhouse from 1970 with 13mm wood fiberboards inside.

Now we're starting a room renovation and we're a bit undecided about what to do with all the walls...

Either
13mm wood fiberboard
6.5mm renovation plasterboard

Or tear down and install
OSB (10 or 13mm)
Plasterboard (6.5 or 13mm)

Right now, we're leaning towards the following:
For exterior walls:
13mm wood fiberboard
6.5 renovation plasterboard

For interior walls:
Tear down the wood fiberboard, insulate, and then apply OSB and plasterboard in the appropriate dimensions. However, there are a few unusual cc measurements (30-40cm) and it seems to be a 55mm frame, making it a bit tricky.

Two questions

• What would you do?
• Which dimension(s) would you choose for the OSB and plasterboard?

Thanks in advance and I'm attaching some pictures as it's always nice.

 

[mxjolle]

The fiberboard smoked on the inner wall anyway when we wanted to insert some insulation. The other walls will get renovation gypsum because it was really not fun to tear down the fiberboards.. 😅