Cheap construction board for filling out?

[Sir Duke]

Good morning!

Renovating a wall. There were several layers of wallpaper, hardboard, plaster, etc. About 20 mm. Now it's gone. I had planned to install standard plasterboard. However, the window frames won't be flush then. Is there any "economy board," meaning a suitable and cheap filler board to place under the plasterboard? Or perhaps some material that provides a bit of insulation?

Thanks in advance!

 

[falkn]

Double up the plaster, either with a standard and a 6.

 

[Stefan N]

Should probably have put a 6mm plywood under a 13mm drywall.

 

[prototypen]

Standard for plywood is 7 mm
What about the option to plane down the casings on the windows?

a renovation plasterboard is probably the easiest.
Protte

 

[Sir Duke]

Aha, thank you all for the wise contributions.
I was wondering if there is any cheaper material. But extra gypsum might be reasonable then.
I'll consider planing, if it can look nice. Or if the frame needs to extend into the room a bit, one can saw from the side.

 

[falkn]

So you are looking for a material that is cheaper than gypsum? Does it exist? However, I don't quite understand what you mean now. Is it that you are referring to the old reveal boards as the frame? In that case, it's probably easiest to split them to the right depth.

 

[Sir Duke]

The wall will become thinner. So the existing window frame will then be too deep.