rim joist replacement?

[d-cubed]

As a buyer, I have a signed P&S on a 1987 colonial in southern NH. The rim joist behind the deck shows a small area of rot from inside the basement (knot area). There are dead ants and ant powder under the deck. I am assuming that a rim joist replacment is in the cards and am trying to assess the cost of the job for my negotations with the seller.

In order to support the exterior wall during repair, can I support it by jacking floor joists in the basement or must I support the wall by other additional means?

[Snoonyb]

It depends on the direction of the floor joists in the area in question.

[d-cubed]

It depends on the direction of the floor joists in the area in question.

The floor joists are perpendicular to the rim joist. Does my method of support (jacking joists in basement) work with this scenario? If not, what else or what different option is needed?