We added a second floor to our ranch style home. The addition is over half of the house and at a 90 angle to the original structure. Plans were approved. 20 years later there appears to be a need for more support in the basement under where the 2nd story addition is. Because it runs at a 90 angle to the original structure the joists in the basement run parallel to the exterior wall and therefore it poses a challenge to support in the basement; the weight also falls between the joists. My husband has tried a variety of jacks in different areas without good results. It has sunk about 2 inches. My husband is handy and can build a structure if he is advised about where and how to put it.

Can u give more info and if possible pictures? Is the whole structure sinking or just one side? Or just one wall or corner? Are the outside walls built over the outer walls of existing structure? Is the sinking only at wall that is seating between floor joists?

With this info we should be able to help u. If unable to give this info, u will need to get a certified architect and /or structural engineer to evaluate.

Chuck

Thanks for replying. The three outside second floor addition walls are built directly over the 1st floor walls; these walls are not sinking. The problem wall is the wall that divides the original structure in half where the 4th wall of the second floor additions is. This is the wall that lies between the parallel floor joists on the first floor.

You honestly need to have a structure engineer look at it. Did you have the plans approved by one at the time, or just the building or code department ? But often a new support foundation under new supports, esp with that much drop. Is the beam holding this bowing,

The wall that sits in the area between floor joists should have a support girder under it. This girder would need support columns to the basement floor and the basement floor under columns would need to have footings to carry weight.

The size of girder and number of columns would be determined by the length of wall. This is a job for a structural engineer to determine.

After footings have set, u will be able to jack up area of wall that sunk before installing columns. Raise wall only about 1/4'' a week until u get it to the height needed. This will minimize damage to finish and give the wall to acclimate to new location.

Chuck