OK...point #1. If any part of your slab is 'below grade' the ENTIRE THING is graded as 'below grade'. Personally I would pick different flooring for the 'wet' rooms such as the bathrooms and laundry. The reason: 'water proof' flooring is expensive. So WHY pay for the entire basement to be covered in 'water proof' when only a few hundred square feet actually 'need it'. The other thing is: a floating floor is really all you want to play with. Tiles in bathrooms/laundry room can be adhered to the concrete, the rest can be floated. The basics for ANY floating floor is the same. You must have a vapour barrier (not always underpadding) and you must always have a WELL PREPARED concrete slab that is flat (no wonky subfloors for a floating floor...ever). A laminate floating floor and a vinyl floating floor and a cork floating floor (and even a linoleum floating floor) all require the same thing. And the mechanism to install is always a 'click-together' system. An engineered hardwood can be floated but it almost always requires glue on the seams. Again, all of the same PREPARATION is required. So go ahead and start paying for the concrete slab to be fixed up so that your flooring of choice can be laid down as soon as you can. The 'nightmare' the sales guys are talking about relates to installation and moisture. They are TRYING to get you to purchase the product THEY NEED to move. Yep. I would hazard a guess that these guys have been given 'targets' to meet and/or they have been offered bonuses for moving a certain TYPE of product (too much in the warehouse is costing the company TOO MUCH money). In a nutshell, the reason why you are getting 4 different opinions is because you spoke to 4 different salespeople with 4 different 'company agendas'. That's it. There is no mystery in that. My questions for you (if I were your sales person): 1. What is your budget (do NOT fudge numbers with sales people...it pisses them off and makes them less likely to get the RIGHT floor)? 2. What is your FAMILY situation? Animals? Landscaping issues such as pools, etc? 3. What are YOUR expectations? Can you accept the limitations of certain flooring if it gets you the LOOK that you want for the price you are able to pay?

First of all, I've taken carpet out of many areas where there were original hardwood floors underneath them. A hardwood floor is not structurally worse than plywood; in fact it is better quality wood and therefore structurally better. So, if I were going to do LVP throughout the home, and I was worried about the subfloor (the plywood part), I would pull the carpet up first to see what is under it. If there is structurally sound plywood under the carpet then you can make your decision from there about the hardwood. You could always raise the carpeted area to the level of the hardwood and do the LVP then, which could potentially save you money, depending on the size of each room.. Or, you can look for a reducer (strip that connects two different kinds of flooring), but that probably won't be your first preference because it will create a lip and looks old fashioned. Second, in my area (midwest) the market for good used carpeting and any hardwood flooring is so hot that pre-pandemic I advertised an entire second floor of carpeting, in good used condition (no stains, but used) on craigslist and within 24 hours it was gone. People came and took it all, padding and everything. Same with hardwood - family members took theirs out, replaced it with LVP, and sold the used hardwood at an overall profit. It is not hard to take carpet out; hardwood can be trickier depending on how it was put down. Seriously, I'm a 50 year old woman and with a claw hammer and some gloves I could get that carpet up in an 6 hour day, pad and all. Two preteens could take it up in half that time. Now if the subfloor is concrete (no basement), then you may have to scrape the glue off when you remove the padding, but even then glue is usually just in targeted lines, not evenly spread all over, so there is not much to get up.

Some vinyl can not be used with any underlayment. MOST cannot, in fact. What needs to happen is your installer needs to be buying all the materisls, and you need to plan on spending more on the prep required to get the floor FLAT than the flooring material or the install. Prep is the key, and its much more involved thsn your casual installer not being involved in anything would havd it. That lack of buying the products, and lack of telling you how it is going to be done, and no seeming mention of the huge smountbof prep that is typical with carpet covered sins, all but guarantees a hack who doesn’t know how its done.

I'm in a very similar situation. I'm considering marmoleum. I really wanted solid hardwood but everything I read says not to put in on a slab below grade. We've lived in the house 7 years and never had moisture in the basement but I'm not sure if that makes it safe to try. What did you end up doing?