Best way to level an uneven floor

This is not a situation I would be prepared to give judgement on without examining the problem on site. It is important to look at the possible causes before recommending a solution

Some one need to see that before you do any self level because that not allowing you a lot to raise the floor whith out braking on the future

Before considering any levelling solutions, the cause of the problem needs to be identified. In the first instance arrange for a local carpenter to investigate, if they are unable to ascertain the underlying cause they may recommend a building surveyor or structural engineer to investigate further. Be aware that a thorough survey may need to be invasive (removing floorcoverings, floorboards, skirtings etc.). Subject to the outcome of a site investigation; if the floor is constructed from timber joists, then these can be re-levelled/replaced/timber firrings added, as required. This work will involve removing skirtings and floorboards etc. Please bear in mind that adjusting/repairing joists may affect the ceiling below, and realigning/adding to the low section of the floor may have consequences in terms of doors, walkways, fixtures & fittings etc. I would be surprised if a deep levelling screed were the appropriate course of action in this situation and would seek the professional advice of a building surveyor or structural engineer before considering that route.

We've seen floor joists in really old buildings that were out of level just because that's how they were installed, i.e. nothing structurally wrong. Levelled them with firrings & new floorboards. Had to adjust one doorway though. Double check if levelling will cause issues with any corridors/adjoining rooms etc. However, best to get a structural engineer in case the unevenness is caused by subsidence or any other reason.