Putting down XPS foam would also cause a impermeable barrier. XPS is slightly permeable, thus allowing water vapour to dissipate slowly. At the same time, it is unaffected by moisture and the R factor the XPS provides keeps whatever material is above it warm enough to avoid condensation from forming. It's not the vinyl that's affected--it's the adhesive that fails. This piece from Dr. Lstiburek details the problems of water vapour coming through a basement slab. (Though it deals specifically with improperly done slabs, the principles are the same.) Loose-lay vinyl may handle the moisture better. However, your floor will likely require extensive work to achieve a level bump-free substrate. Since you indicated some family members are more than 6'6" tall, I would suggest that tile over a crack isolation membrane might be the best solution. Or you could lay low-pile synthetic carpet without an underpad and just count on replacing it every few years. When I had rental properties, that's what I found myself doing because of tenant damage. Always lots of ends of lines, oddballs and returns available at discount stores and on Kijiji.

The cost of a PROPERLY laid micro-topping that is then polished/ground to a high-level finish will depend on whether or not the current slab has an existing/functional moisture barrier. Some of the SUPER HIGH END microtoppings that are DESIGNED to be polished (no epoxy coating) to a super-dense finish, are very expensive. They can take close to 2 weeks to grind down the existing slab, then put down a moisture barrier (spray-in-place x 2 coats), then primed, then the micro-topping is put in and then all the grinding to get a closed-pore floor that is almost impervious to stains and etching (almost...but not quite). And a professional concrete flooring specialist isn't cheap. The level of "polish" will determine your costs. For a DIY level finish = $5/sf (which stains and etches and takes ++maintenance and ++ polish/wax). A medium grade finish (professional level) WITHOUT the microtopping = $7-$10/sf. A high-end (almost bullet proof finish) which includes the microtopping = $15 - $20/sf. And then the actual costs will depend on your location and the ease of access to all of the products/professionals you need. If you are rural without access to a large city, then the cost is going to go up. If you are in an urban location with LOW wages, then you are set for the lower range that I've listed. If you are in an EXPENSIVE urban location (think NYC) then you are in for the HIGHEST range I've listed. But until you decide which type of FINISH you are after, we can't help much more than that.

You are all amazing. Thank you so much for your input! I believe you've answered my question about cost savings. I do believe you've convinced us to stick with the basement. So a little more information and reasoning for this layout, which I agree is a little different.... We're in our mid thirties and we have 3 young daughters. We live in a split level with garage below, and I gotta say, it's not my favorite setup. Unloading kids and carrying everything upstairs is hard. He's a farmer with a wide array of hobbies including hunting, skiing and camping, and there's a lot of crap that goes along with those things. I'm a simple woman with few passions other than working full time, raising babies, taking care of chickens and making soap. Our current yard is a steep hill with our home in close proximity to a busy highway. My girls will never be able to ride a bike or play with a ball at this property. So we desire the following in a home: Accessible main level for aging parents and of course for us in the future. The front entrance of our plan has a concrete sidewalk ramp. Attached garage on main level with plenty of space for farm truck, SUV, his old Camaro, ranger, mower, saws, tools and a workbench. A decent sized mudroom/ laundry room. Four bedrooms, 3 bathrooms. I'm thinking of 3 teen girls getting ready in the future. Walk in pantry. I have home canned goods and canning supplies. It'd be nice to have space for that. A secondary living room. I want this to be a romper space for my growing kids, their cousins and friends. The less breakable things, the better, in my mind! I see a lot of movie watching happening here, and a windowless den would be fabulous. A second kitchen for entertaining, which we do quite often, and for soap making. This is a messy hobby that also comes with a lot of stuff that takes up space. The craft room and hunting rooms.. these are on my wish list. That whole end of the basement could just remain unfinished storage. But how nice it would be to have designated space for his hobbies and mine. Really, I'm okay with no windows in those rooms! Anyway, we've put a ton of thought into these plans. It is essentially a whole other home in the basement which I know is a lot of expense, but something I'd like to explore at least. Thank you again for answering my questions! our current home :)

I'd want to figure out where the water is coming from-- up from below or down from above. If from above, then fix the grading, downspots etc that are allowing water to flow into your house. If that solves the water infiltration problem then dig out the junk, put down a gravel base and a slab on top of it. If up from below then you probably really do need a sump and that's probably an ideal place to put it. Jackhammer or otherwise remove all of the patch material, dig out good size pit (maybe 3 ft deep and as wide and long as the missing slab, line it with permeable landscape cloth and fill it with gravel, with a plastic sump shell set into the gravel to provide a place for the pump and for water to gather. Then you can put a proper slab on top of the gravel, leaving the access to the sump open. If you are also doing radon remediation they may tear up a bunch of your floor anyway to put piping under the slab, in which case you can piggyback on that work to add a french drain system leading to your sump. Talk to your radon contractor about what can be done. You will certainly want to complete the slab to prevent radon migration through that spot.