We are replacing our kitchen cabinets, but not the flooring.

We are also adding more cabinets. The problem is the tile flooring does not go under the cabinets.

So some cabinets would be sitting on existing tile, and some on the concrete floor below the tile.

Should I fill in where the tile is missing with scrap tile to get a more level surface to start with - I am trying to use pressure treated wood to fill in where the missing tile was but its not quite thick enough.

Thoughts? ideas?