Add insulation?

[Calle Schewen]

Hello!

I'm replacing the siding on part of the house and under the siding, there was... an old siding! The distance between the current siding (red) and the old siding (yellow-white) is about 2.5 cm. It's the red siding that I'm redoing.
Is it a good idea to add insulation before I put on the new siding? What do you think about outdoor drywall?

 

[Stefan N]

The insulation value of gypsum is basically zero, and it's also good to have an air gap behind it.

 

[fribygg]

What is the purpose of the panel change?

 

[Avemo]

How much were you thinking of extending? I don't think you'll find insulation boards that are 25 mm. And it's common to want an air gap. How much insulation is already in the wall?

 

[-MH-]

Could this be something?

https://hunton.se/produkter/vagg/hunton-vindtat-plus

 

[Calle Schewen]

What is the purpose of the panel replacement?

I want to paint with slamfärg, and the paint currently on it is old plastic paint.