Some months ago I removed a partition wall with a doorway to increase the size of my kitchen to incude a diner. Over the months I have notice that my first floor landing as become creaky and there is a noticble 5/6mm gap between skirting and floor, in a 4/5 foot section directly above where I removed the the partition wall. I,m guessing that that the new span of the joists from wall to wall of 24ft has been affected by the removal of the wall. My question is what is the best way to support this. I will have access to just one outside wall, the other side of the kitchen will be an interior wall. There is no internal brickwork, just stud walls.