u/Fun-Food-6132

Hello! First time posting here so I am trying to provide as much info as possible. Thanks in advance for the help!

We have a contractor coming in a few weeks to finish part of our basement, and we are going to be DIYing the flooring. I want to make sure I’m doing the flooring right and figure out if I need to finish this before the contractor comes, or if it could be done after.

Background:

• House built in 1998, western PA climate
• Poured concrete floor, very flat. About 5ft below grade
• Likely vapor barrier underneath (moisture levels vary between 30-60% RH)
• Walls are concrete blocks
• We have a radon sub-slab depressurization system installed in the portion of the basement that will remain unfinished
• A contractor will be finishing the walls with XPS foam board + rock wool insulation + mold resistant drywall + treated wood studs 
  • The rigid foam board will be taped to create a vapor barrier on the walls
  • He is not going to finish the ceiling, just paint it
• This will be an enclosed space with climate control (forced air vents)
• Size is about 230sqft (approximately 11’x21’), it will be used as a workout & play room
  • This is about 45% of the overall basement, the rest will remain unfinished with a separating wall
• For the final layer of flooring I am thinking of doing padding with carpet tiles

Option 1

• 3/4” OSB subfloor
• 2” XPS foam board - R10

https://preview.redd.it/s9trw85cyezg1.png?width=1556&format=png&auto=webp&s=443d8e648a72c2d3ae2f7127f6aa0b3a7a5bde5a

Option 2

• Dricore subfloor R+ - rigid foam with grooves and OSB top as subfloor - R2.7

https://preview.redd.it/jhbd8s7dyezg1.png?width=1538&format=png&auto=webp&s=31038e9fd499bca3518415ee6835a7d8fc3b06ec

Dricore has foam with grooves to allow moisture to move/evaporate:

https://preview.redd.it/0y41r3udyezg1.png?width=1324&format=png&auto=webp&s=71534c5beb1abe0b3378fd83ea0dd011a7105c1a

Questions:

1. How concerned should I be about water?
   1. Do I need a vapor barrier? How should I create one if so?
   2. If I do need a vapor barrier, should it seal with the one on the walls?
   3. Should the floor assembly be vapor-open or vapor-closed toward the slab?
2. What R level should I be targeting? The basement floor gets quite cold in the winter, but I don’t have measurements 
3. Do I need to leave space for expansion along the edge of the wall, or can I run the foam/subfloor right up against the drywall (or should it go against the blocks)? In my diagram I don’t have a gap
4. Should the floor be installed before the studs/drywall, or can it come after?
5. Are there other options I should be considering?
6. Should I consider a different final layer? Perhaps LVP with area rugs?