Here are a few options: 1) If you'd like to nail it to plywood, install FloorMuffler over the plywood. This is a sound proof, moisture protection accoustic underlayment. 2) If you'sd like to glue down, use Taylor MS adhesive. It has a 25% noise reduction. Best Installation: Nail over plywood with FloorMuffler. My kind regards...

As Greendesigns points out, laying hardwood over concrete is tricky. A permanent hardwood (glue/nail/staple) on slab is more likely to go wrong than right. To be crystal clear, you can GLUE DOWN hardwood STRAIGHT to the slab. Adding plywood is a step used to NAIL down (or cleat/staple) hardwood into place over slab. You can SKIP this part if you GLUE DOWN the wood. But....and this is a MASSIVE 'but'....the professional must be SUPER EDUCATED as to glue down technique, glues, trowel size, coverage, moisture mitigation, etc, etc, etc! Gluing down hardwood is no different than gluing down plywood. Both are wood. Both require the same adhesives...and both have the same failure rates (ie the 'rotten plywood' comment above). The next issue would be height variation. I would expect a transition. Even a small one. And the reason: the townhouse subfloors were BUILT to accommodate cork glue down tiles (probably 4mm) in the kitchen and then another floor in the living space (???original floor???). And this BUILT IN floor height variation will never go away. Not unless you go back in time and make all of your decisions based on the inclusion of the hardwood running into the kitchen. I personally would find out if the engineered hardwood (with the 4mm wear layer) can be FLOATED - most are allowed to float...but not all so it is best to be super prepared. If it can be, your situation has been solved....remove the old vinyl/cork and FLOAT the new hardwood in the kitchen. A thin sheet of plastic will be laid down over the concrete and the wood will be floated over top. You will have a small transition ANYWAY (floor height variation = transition) so you might as well change the type of install to MATCH your slab = floating hardwood = MOST APPROPRIATE form of wood flooring install over slab. Also be aware that the finish might have a slight colour/gloss variation. Again, that's where a well prepared transition strip/area can be SUPER helpful in hiding these slight variations.

Hi @Lynn Morford, I hate to jinx things, but now three months in, I LOVE the floors. I fact, I admire them many times a day (good distraction from current CV craziness). There are about a dozen spots where there were dings or tiny cracks, which freaked me out at first, but I'm pretty sure it was just from the movers. I do take care of them like a newborn child, though--sweep, vacuum, wipe, repeat. Overall, I'm very happy with them! @everdebz, we ended up gluing down. Definitely harder on my body that floating but I've learned to wear slippers or socks and I have yoga mats in most rooms to give my feet a little vacation as I walk through the house, lol. In the end, I trusted @joseph_corlett's comment about letting the contractor make the call on what is best for the situation. Granted, I still pine for the perfect floating feel of my old Junckers flooring, but apparently theirs were unique and most other flooring can't float the same way, so... Anyway, the sad fact is, you can't remove glue-downs without destroying the boards. So fingers crossed you never have to! (I put fake wood in my laundry room and we've already had three floods, so thank god for that decision.)

Is there any way to measure the temperature at the 'wood-subfloor' interface? Most floor products do NOT allow anything warmer than 85F at the subfloor-floor interface (the temperature found between the two products). The 60 F INSIDE temperature is quite low. It is just on the very edge of "indoor living temperature". Most warranties (paint, carpet, hardwood, baseboards, doors, drywall, cabinets, etc) must have consistent indoor living conditions. The building industry has a definition of indoor living conditions (which are to be maintained throughout the life of the home...regardless if someone is home or not). Relative Humidity: 35% - 65% Temperature: 55F - 85F Your indoor air temperature is only 15 Celsius. That is VERY cool. The lower temperatures have a harder time 'keeping' moisture in the air. That's why you find dew on the grass during the chill of a spring morning. The grass is colder than the air. And the air is already quite chilly. The air has a hard time 'holding on' to the water vapour. The cooler blade of grass is JUST ENOUGH to cause a water droplet to form - pulling the water from the air and onto the earth. As the air warms up, the vapour is HAPPILY stuck in the air. That's why you have hot-sultry areas (like NYC in the summer time) and you have cold DRY areas (like Mongolia in winter). It's how the laws of physics work. I would tip up the heating a snick and OPEN THE WINDOWS to pump up the humidity. I would bet the closer you get to 50% RH and 70 F (20 C) the better your floors will look. Somehow you need to get the humidity and the temperature up AT THE SAME TIME.