Expansion strips for this purpose are available from the building supply.
Lowes, Home Depot, etc.
If you use construction adhesive, along with a few Tapcon screws and
large diameter fender washers, you can mount it to the garage wall at the
proper height and use it to screed the concrete to the proper pour height
and slope. I did this to a carport add-on last year and it worked really
well.

RJ

"JB" wrote in message
...
I'm expanding my concrete patio area with a 10' X 10' square slab. 2 of
the side butt up against the original concrete slabs. The third side butts
against the back wall of my garage which is brick and the 4th side butts
up against soil. I have dug it out and laid in gravel.
Question. What, if anything, is used for expansion between the new slab
and the old concrete as well as the new slab and the brick wall?
Thanks for your help.