Yikes. Sounds like the floor might need to be re-leveled all over with more self-leveling compound if it is that bad. I'd maybe cut my losses and find another contractor that can do it right, maybe ask the current contractor to pay for the repairs because you don't feel comfortable with his proposed solution. Look into Laticrete products for everything, as they have some very advanced products, and you can call and talk to a product specialist at any time. If you have a ProSource in your area, they'll carry Laticrete at good prices. Laticrete reps might even be able to provide you with suggestions for an add-on underlayment if you cannot re-level. They have some self-adhesive underlayments that are fairly easy to install, but again, getting that floor level first would be the best route.

The low areas need to be filled, the high areas need to be ground, or a combination of the two.

Thank you! That’s what I figured, but making sure I’m not in left field.

All the flooring needs to be removed, the entire subfloor has to be ground/leveled/ground to get it within the specifications for the vinyl and then the floor needs to be reinstalled.

Check your contract to find out how much you PAID for subfloor preparation. After tile has been jacked out (which is your situation) it can cost $2-$4/sf for subfloor preparation.

If you paid $0.50/sf for preparation (not including tile removal) then you got what you paid for (sad as that is). If you paid $5/sf for subfloor prep (not including tile removal) you have been cheated.

If you paid $0,50/sf for prep, you will need to increase the amount of money paid for subfloor preparation. In other words you need to pay the installer MORE to deal with this subfloor.

If you paid $4-$5/sf for subfloor prep, your installer OWES YOU a lot more work...you don't owe him/her anything.

Again, you have to go back to the contract to see what you paid for preparation of the slab once the tile was jacked out.

Thank you! I will look at this to see what we paid, not sure off hand.