3650 PSF is equal to 25 PSI..... Their dricore products are just massively overpriced, at least in the US they are. I think it is better to put down a foundation wrap (DMX), then 1" XPS foam (25-30 PSI). Assuming that the floor is flat, you could probably get away with putting flooring (with a membrane) directly on top of it. If your floor isn't flat, you probably will need a dedicated subfloor. I'd also be sure to use some kind of flooring that is somewhat rigid and install it perpendicular to the foam boards, so that if the foam boards do try to lift or sink, the flooring will add some rigidity to prevent it from mattering.

The only way to do it correctly is to glue the carpet to the floating floor. Later when you take it up both floors will come up together. It is an unconventional way to do it but it will work if done correctly. The carpet and floor will expand and contract together so there will be no buckling of the floor which is a possibility if you try to nail tack strips through the floating floor. Another way to do it is to saw all around the floor about 2 inches from the walls. Then nail the tack strips to the bare floor. In that case you can also install padding as usual (gluing it to the existing floor.) But, it would probably be cheaper to just take up the floor. The only part that may be troublesome is removing the baseboards. I have installed all types of floors for over 40 years.

I did both. I was taught by an installer how to flush cut the flooring to butt up against the tile, which did have an edge strip, with a 1/16th (I think, it’s been almost 2 years) gap and silicone caulk. I hated it because the flooring is matte and I couldn’t find a caulk that wasn’t shiny so it left an obvious shiny line between the tile and the laminate flooring. I replaced it with a transition strip. I do remember messing with the strip to making it as flush as possible between the two different floorings, I think we had to modify the metal piece inside or route one side deeper. keep in mind all of this was DIY and with proper planning by a pro installer the different floor levels are taken into account. I changed my mind and decided to tile the powder room when the flooring was already in. Also, in this scenario the ends are supposed to be sealed and caulked beneath the transition strip in a powder room application, even if it isn’t “wet,” like with a shower or bathtub. That was so deep in the specifications for the flooring we almost missed it. I did not use a transition strip by the front door. I intended to, just to be cautious since we spanned a greater distance, but I hated how the strip looked. Next to the threshold the caulk is invisible, even though it’s shiny. We were pressed on time and budget because it was a new home without any closet shelves, garage storage, or landscaping. The idea of replacing the carpet that was falling apart (after less than a year) with more of the same carpet by the builder was discouraging to me, so we really couldn’t do anything differently. But in a more predictable world, if I could have wrangled a couple thousand more, I have done a simple, not engineered, hardwood and installed it ourselves. The laminate has not had any issues at all as far as buckling or drifting. It’s on our main floor and the only place with an issue is where my kids drop ice cubes on the floor in the same spot and don’t pick them up. There isn’t any swelling or peeling but there is a thin line where you can see the composite is a different color. This is not in an area with a long span. The LVP with equivalent numbers of pieces were 2-3 times as expensive.

@ Marion...I'm glad you are embracing the floor. A professional stone restoration company can come in and give your floors a good scrub and a new layer of sealant. Just doing that can perk up these floors quite nicely. I'm not sure of the price range but I would be surprised if it cost more than $3/sf. As for the other floors, carpet does very well over them. It's what makes carpet unique among floor coverings (sigh...I know...so many people hate carpet...but Canadians have it everywhere). It is supple and easy to lay over odd surfaces like your floors. I also like it because it offers the SMALLEST floor height transition from one room to another. Like hallway - bedroom, etc. The adhesives can be dealt with when (if) you ever choose to uncover these floors and live on them again...until then I say go ahead and do what you need to do to enjoy your home.