Historic building with tricky connection

[Ben29]

This is an existing 4-story building. It is essentially a brick row house on steroids. We are having an issue at the 4th floor where the brick bearing wall is tilting outward because of how the roof is bearing on it. Please see photos and sketch below.

It is essential that we preserve the way it looks from the outside. My first thought was to build a new bearing wall inboard of the existing wall, and reinforce the existing floor joist to support the new bearing wall.

 

[Ben29]

 

[phamENG]

I think you're on the right track. You'll also want to grab that front wall and tie it back into the floor diaphragms. Easiest and most effective method is, of course, the little star plates on the outside, but as long as you can get in and grab to just past the center of the wall is better than nothing.

 

[GeorgeTheCivilEngineer]

Check the connection from the floor joists to the wall. If they were just relying on friction then may have moved away. The wall should be strapped back to the floor plate.

I would think that would stop most of the movement.

If you wanted to do more then either additional restraint to the wall below (green) or a beam at the roof line change (red):

 

[XR250]

You could also do something like this that would not require loading up the floor joists meaningfully...

 

[kipfoot]

Yes. New beam either above, at the break in the roof slope, or below your new wall. Of course, your wall will be in segments with headers at the three dormers.
I'm assuming that the joists span side to side, but the floor boards in the photo and your section suggest they bear on the front wall.