I thought vinyl was good for basements (or at least okay to use there) b/c of watching too many home improvement shows where they've put the vinyl "wood" strips on the floor, saying it was a better option than laminate flooring. I want to scream every time I see this hunk from Canuckistan finish a basement using fiberglass insulation and a vapour barrier. Vinyl in a basement over a proper underlayment such as Delta FL is unaffected by moisture and resistant to mould. This post was edited by worthy on Wed, Oct 9, 13 at 12:24

If the joists are rotten, how do you know the flooring isn't? I know it's more work, but if you were to rip out the floor, it would be so much easier for you to work, I assume the crawlspace is fairly cramped.....I can think of nothing better than being able to stand up to work. In order to prevent moisture creeping up into new joists, you need suitable damproof course between the piers and the joists/bearers, but before you totally seal the underneath, shouldn't you ascertain where the moisture comes from? Presumably you're in a cold climate, and I know that dictates different construction methods, but I used to live in a warm, moist climate, (Australia) and the big priority was to VENTILATE sub-floor areas, to keep them dry.

My basement is half finished- 75% is painted concrete, walls/ceiling are extremely thin 1940s gypsum wallboard mounted to 1.5x3s. The exterior perimeter walls are skim coated with cement it seems, and done a long time ago. This is a 1904 house in Seattle. No drain in the floor. Ceilings are 6.5' (6' under the support beams), so I'm not about to spend a lot of money or time here. What I'd like to do is make the larger area a kids playroom and a TV room, and make the smaller rooms a laundry/storage and a gym. The basement seems pretty dry. It certainly does not have any odors or noticeable mold spots. Some minor efflorescence spots in the walls and floor, and some smallish water stains of unknown vintage or even origin, but overall it kind of just has darker spots and areas on the wall- we have not seen any water intrusion. In major storms the walls may turn a different shade in spots, but no water inside. Drainage is under control outside as far as I can tell. I run a dehumidifier to keep it at 50%, otherwise it would be in the 60s. First question- the floors: I'd like to put something cheap down. I'm thinking carpet tiles in the play area, and vinyl coin pattern rolls in the gym and laundry. Not a big fan of painted concrete really, I'd probably just leave it as is if that's my best option. Do I need to bother with any type of underlayment? I'd do something thin like Delta FL if I had to, but I'm imagining having to rip that up along with the floor anyway if we ever have a real water incident. It would be nice to have less coldness underfoot, but I'm cutting it close on ceiling height in the gym and don't want to spend a lot of money here so real underlayments are a nonstarter. I don't want to introduce mold issues either though. I know it's always a crapshoot with basement floors, but what are my realistic chances of being 'fine' just slapping something like vinyl or carpet tiles down and keeping an eye on them? Now for the walls: The areas are not that big, so if I don't have to go with 2x4 framed walls I would probably opt not to. It's not particularly cold down there and there is heat as the PO had an office of some sort (there are like 10 old school phone jacks). I don't know what insulation would really get me and I'm fine with space heaters. I'd just like to make the walls look nicer, especially in the gym where the concrete is pretty rough. I'd probably be fine with posters or mirrors or something to be honest, but I don't think those should go on the bare concrete below grade... The other rooms are smoother and fresh paint may do the trick. Do they make pressure treated shims or something for the thinnest possible frame? What other options should I consider?

Okay that helps, KT. I think the finished wood trim won't work here as it seems you're going more farmhouse... I also (just personal preference here) wouldn't do beams (or faux beams) as "supports". I would leave it at the drywall. You could add simple matching corbels to finish of the corner like this (but the other direction, obviously) I like the brick, also...(again, obviously it would be on the ends only) Just food for thought...