Opening in plank wall

[jackass]

Hello
I am planning to make an opening in a plank wall in our 1.5-story house, about 80-90 cm wide to start with. The wall consists of vertical planks with a horizontal plank on top. Above this is the sloped roof.
It is the vertical planks I want to remove. Is this risk-free, and if so, at which dimensions? Does it matter if there is a roof truss above the planks?
If I need to install a header, how can it be done most easily with minimal reduction of the opening’s height?

Best regards
Jonas

 

[Jonatan79]

As long as you don't touch the roof truss or a replacement of the previous truss, you can just go ahead, be careful from the start, and it should be fine. By the way, how thick is the wall?