Piles for stronger posts

[yonna]

There is a frame construction along the wooden decks. The posts are 100x100 mm. Do you have to replace the plinths if you switch to sturdier posts?

 

[Testarn]

Probably not. The plinths are supposed to support the entire deck, and a few new posts will probably not weigh significantly more than the current construction.
It's a bit of a wild guess, but without photos and a better understanding of what kind of posts are to be replaced and how they are attached, it's hard to say more.

 

[yonna]

Probably not. The pillars are supposed to support the entire deck, and a few new posts likely won't weigh significantly more than the current construction.
It's a bit of a guess, but without pictures and a better understanding of what kind of posts are being replaced and how they are attached, it's hard to say more.

The frame construction should have much sturdier posts (you can see it in my photos), but that was something I economized on when the house was built. The framework is on both long sides of the house. The replacement would be purely aesthetic.

 

[Testarn]

I can't see any photos?

 

[fribygg]

If you mean your pergola, it should work fine to switch to thicker timber.