" Any suggestions on how to remove the adhesive and what product(s) to use? " flooring razor scrapers and alot of blades. We do not use adhesive removal product because they can have adverse reactions with the future adhesives if not properly removed 100% or neutralized. " I'm curious: if the laminate can go over the tile, how come the engineered can't? " as jerry_t stated, some can if they are floated, but if glued they cant because the glue will be sticking to the tile, so it will only be as good as the tile that is installed. If you do glue over the tile and have a lose tile, or if some becomes loose in the future, the wood also becomes loose, becasue it is glued to the tile. This is why removal is important so it sticks to the concrete slab.

You need to do a little more archeological digging still. You need to know the whole construction of the floor before you can decide how best to install something new. I'd take up that plywood piece in the kitchen and see what's under it. It's higher than the surrounding floor, so needs to go. You should also be able to see from there what subfloor is under the original kitchen hardwood. It's too bad the space under your entryway is finished, but I'd still do some exploring from below to see what's under there, and to figure out the fix to stop it from squeaking. Is it drywall below or a drop ceiling? I know it probably seems like a pain to tear out drywall, but if you cut out a clean patch, like 2' x the width of the joists, it'll be relatively simple to repair. Just make sure to cut it down the center of the joists so that there's room to screw the patch piece to it later. Cut the hole under the area that squeaks the most, if you can. Have someone walk on and watch the floor from below to see what's moving. It might be as simple as pounding in a couple shims from below, or face-nailing a loose board from above. You want to find out what's underneath the hardwood. It might be laid directly on the floor joists, or there might be 10" wide boards that the hardwood is nailed to. Another thought is to take out a board in the hallway, since that's not original and you want to replace it. See what the subfloor is there. I am a bit puzzled at why, when you've stripped the kitchen down to the original hardwood, it's still higher than the hallway floor. Is your current surface perhaps not the original kitchen hardwood? Peeling back the plywood area will help determine that. BTW, I haven't heard of that stop squeaking product you linked to, so can't offer any personal opinion. And don't pour self-leveling compound over top of hardwood. It needs to go over plywood.

Hi Mike, Lots of the people here have their cabinets installed directly on top of their hardwood floors (me included). No need to cut it up under the cabinets. There are a couple benefits to that approach, mostly that you can reconfigure cabs/layout etc. later on and not worry what the flooring footprint is. Hardwood will expand/contract, definitely, but it's usually so minimal it shouldn't deter you from just putting your cabs on top and calling it a day. HTH!

SJ McCarthy, thanks for the tips about cork vs foam. We're not house project newbies - we've done drywall, built-ins, moulding, baseboard, window framing/trim, etc - and actually installed nearly all the baseboard in our house so removing and reinstalling is a non-issue. Our house has just five rooms. The hardwood goes from the living area straight into the bedrooms (continuous) so no transitions there. Where it transitions to tile in the bathroom and kitchen/dining area already have drops (the hardwood is lower than the tile) so adding laminate on top would make the floors more even or just reverse the drop slightly if anything. Edit: We measured and there is currently a 15mm drop from our kitchen to hardwoods already, so adding laminate on top would help there. The interior doors are ones we already replaced and trimmed to fit (so nothing new there), but it would be ideal to not have to shave them further. I would love to find a floating floor that can go over what we have without requiring us to shave the doors more so that when removed the doors wouldn't have a weird gap over the hardwood. Update: Hubby informed me that the four doors we have that open over the hardwood each cost about $30, so shaving them further is a non-issue and replacing them in the future is also a non-issue. The door frames trim is already higher cut (we cut little spacers to put under them to make them flush with the floor) because carpet had previously been installed over the hardwood. I'm not opposed to using a different material other than laminate either, I just don't want to have to move myself and everything out of the house only to pay a lot to have our floors redone and then have them look worn in another few years. With a floating floor we can do the install ourselves and do it piecemeal, one room at a time, which is logistically a bit more manageable. We also wouldn't mind changing the up the color of our floors a bit, so laminate would allow us to do that while maintaining the integrity of the existing floor.