We are rennovating a kitchen and have discovered a lot of notching in a load bearing wall.  The top plate has been notched or cut through in several places.  I can get a simpson strap on most of them, but there is one notch I can’t figure out. 

The top plates have been notched about 1/2 way to make room for the 4″ iron stack but the stack itself is only 1/2 buried in the plates.  They nailed an assortment of 1x and 2x on to the studs and all the way down to the subfloor to create a 6.5″ wall cavity.  Basically I have a double thick wall with only one set of bottom and top plates.  The builders also added a piece of angle steel to tie the top plates together, but it is nailed to the 2x strips nailed onto the actual studs (see picture) so the inspector is not happy with it.

I was thinking about tearing off all the built up 1x and 2x and just building another wall right in front of the original but I would have to notch the top plates of the new wall to fit around the other 1/2 of the stack.  I would end up with solid wood on either side of the stack but is that sufficient?

One last complication is that there is a big iron riser clamp/hanger holding up the stack that is resting on the “added” 2x pieces.  I think I can incorporate that into the new wall, however.