Beef up existing slab or demo? (house, plan, space, room)

[Cacophany]

We have a small gable ended one room cabin we want to add a bathroom off the shedroof side. Originally it was supported on the shedroof side with 12"x12"x18" concrete footers which remain. The main room is double walled rock all around so very stout already.

We poured a four inch or better slab with rebar, plumbed in for all the fixtures, and now want to change the design. The shedroof steals alot of room and we decide to make a tower instead, but we didn't plan for that height when pouring the slab. All the contractors seem to want to tear it all out and start over. I'd like to avoid that if possible. I'd like to tear out the corners on either side of the 9x9' space next to the house and beef it up some way. I've heard in another part of this forum of coring at ? depth and supporting the corners.

The perimeter on the other sides could be compensated by pouring another footing adequate for the extra weight to my mind.

Any advice greatly appreciated as we really don't want to tear up the plumbing and starting from scratch unless there's no other way.

NO earthquakes here....or codes for that matter. Thanks!

[stevo6]

I can't visualize whats going on. If this is a stone walled cabin I would want to get it right, thats for sure, Any way to scan some sketches and post?

[Cacophany]

I'll see what I can do. I have architect drawing which is too big for my scanner. I may be able to draw something up a little later...not sure how to attach scans to this forum. Any tips?