Tie in new foundation to old foundation.

I am building a major addition to a garage/upstairs apartment in Vermont. The current garage is a slab with no frost walls (apparently). I will be building a basement foundation next to it and connecting the two with a slab breezeway (breezeway is enclosed and part of the living space – everything is also connected structurally and has connected rooflines).
What are the issues with movement in this situation? The garage is a heated space using a ceiling propane blower heater and the breezeway will be radiant heated. I am planning on adding insulation around the garage to help keep frost out.
The foundation guy and and the excavator and 2 builders have said that there should not be any structural issues as long as everything stays heated and frost stays out from underneath the slabs.
I attached 2 jpgs. The first is the floor plan. The current garage is on the left. The other is a 3d sketchup image of the overall design plan. The garage here in that one is on the right.
Any comments or ideas to allay my fears of this and provide any ideas to make sure frost stays out are welcome! Thanks in advance.
Matt
Replies
You want the slab to remain on the same plane. Rotohammer some 1/2 or 5/8 horizontally into the existing slabs and drive suitable pieces of rebar into the holes. This will only take a couple of minutes with the proper tools.
Hi Matt,
Fancy meeting you here!
I'll let others answer this, as I've already put in my 2¢.
Solar & Super-Insulated Healthy Homes
i'm not real sure i understand what your doing,but i tell you my deal. had a basement and came in and excavated for another basement under a new addition. where there is a dry line between the two i have had alot of problems with water.
i was told later that the basement guy should have made a groove in the old wall and inserted a copper or aluminum spline,then poured the new wall to it,that way there is something to hold the water and make it go to the footing drains. did that make sense? larry
if a man speaks in the forest,and there's not a woman to hear him,is he still wrong?