Levelling multiple floors

[danr86]

I'm looking at renovating a Victorian house and the floors have some rather large dips (probably due to the usual undersized joists). I haven't been able to check yet whether the joists are sitting fine in the walls but will do so. In terms of levelling each floor out (the dips range from 3 on the top floor in the loft, up to 9cm on the ground floor) I just wanted to check whether the below makes sense.

Jack up ground floor joists 1/8 inch each day using a bottle jack using a large beam perpendicular to the joists until totally level.

Add sister joists with M12 bolts and square plates or joyner bolts.

Add noggins / bracing- is this overkill?

Remove ceiling from floor above, repeat above steps.
Add again for the top floor (existing loft conversion - date unknown).

Any other suggestions / thoughts.

Thanks in advance.

 

[cdbe]

You're wasting your time trying to straighten the old joists. Just sister with deeper ones that will span the (deflected) depth of the existing. On the ground floor I would have thought 90mm is a bit much for simple deflection but if that's all it is I would just replace all the joists as they can't be much use for anything.