Replace floorboards and indoor joists.

[jonaslatt]

I have an older house with a basement that has been completely renovated and extended by 70 sq m. At the same time, the old part was remodeled.

But in the older section from '59, the floor creaks and sways.
The problem is only around the chimney breast. All the floors around the chimney breast.

I assume it has become warm, and perhaps the joists underneath have warped or something similar?

I painted a nice picture
I have the most concern with the blue area.
And there I want to tear up the laminate and the floorboards.
The floor is "split" in the yellow area, so from there, I can break everything off.

If you remove the floor, the boards, can you cut off the joists and replace the bad/all of them, or do they support the house's stability so you have to try to fix the uneven ones and leave the original?

Maybe it became a bit confusing now.
Hope someone understands. Attached is a picture.

 

[justusandersson]

The chimney must pass through the floor structure, which is therefore supported around the chimney. I believe your problems are related to this. You need to expose the floor joists in front of the chimney where you have your blue marking in order to study the problem more closely.

 

[jonaslatt]

Okay. But can you cut it off just like that? Or do you have to cut one at a time and fix them?

 

[justusandersson]

There is a supporting rule that goes right next to the chimney (horizontally on the drawing) on both sides. If this rule is damaged, it will become unstable. You cannot cut off any rule. Bad ones must be replaced.