||05-02-2012 12:02 PM
I think you are asking the wrong question. Of course you can jack up an exterior wall. Of course the exterior wall can be resupported. You may be able to force the floor back to level by performing these actions. However, isn't your real question can this addition be returned to (presumably) original condition, level, square, plumb, without destroying the addition in the process?
Totally different question, and of course the answer to such a question requires a thorough, careful analysis of the cause of the problem, evaluation of alternative solutions, and selection of the best solution. Not likely to happen over the internet. The best you can hope for over the internet is if you post pictures with a description of each photo, and you take some actual measurements to see how far out of level the floor is, and how far out of plumb the walls are. Then perhaps this forum can point you in the direction of finding an optimum solution to the problem.