I think I found my new home!

[WernherVonTrapp]

Originally Posted by frau kaleun

Yeah but the real problem is how to raise the counter up in the middle so I can get anything in there. I can push/lift it up a bit but I can't hold it up while I put a permanent support in place. That's why the jack etc. was suggested. I was thinking just of some wedge type things that I could push into gap, starting near the end and then working my way towards the middle and raising it up little by little as I go. Once I got the middle part raised up enough I could slide something permanent in there to fill the gap.

Well, IF you can get underneath the cabinet (via doors, any opening) without too much difficulty, you can get a piece or two of 1" X 6" pine shelving, cut to the proper length you need, and gently tap them into place with a mallot or hammer, sort of along the lines you see in the illustration below.



Once you get the shims in place, get a piece of 5/8 plywood cut to a fitting length, and replace the pine shelving with the plywood, or just add additional pine shelf pieces until you have an inner wall within the cabinet wall. If you use the right glue and a few strategically placed screws, you'll never have to worry about it again. If you're talking fractions of an inch, this might be the answer.