Hi,

I’m renovating our basement and looking to chose the most suitable flooring options. Plan is to install mostly carpet with one section of rubber gym flooring for exercise equipment. 

House is in Alberta, Canada, (Zone 7A?)  with zero prior indication of any moisture issues. 1970 build. Very dry house. 

There seem to be contradicting info on what is suitable. A local flooring supplier suggested they would just use 9 or 10lb underlay straight on the concrete with carpet on top (no vapour barrier, option for spill guard) and then for the rubber matting, install this straight on the concrete. Previously there was just underlay and carpet, and didn’t see any issues. However many other guidelines suggest vapour barriers are required, and installing rubber matt on concrete may create mold issues. 

Understand this may work as it is so dry here, but I don’t want to have to redo any work due to to mold build up under the rubber matting, and I would have thought this is not the best thermal performance for both carpet and rubber matting sections. 

My options seem to be:
1.subfloor made up of rigid foam with OSB on top. Underlay then carpet / rubber matting. Problem this would give an uneven step down into basement. If code will prevent this (I will have an inspection) then was thinking could make an extra deep final step (~3ft) so I could get away with the different height. 
2. that plastic dimpled sheet (DMX) under the rubber matting. Underlay with a vapour barrier under the carpet. No insulation benefit by at least helps with moisture.  
3. as suggested by flooring company – straight onto the concrete
4. the pre-made dricore 2 x 2 panels. 
5. the rigid foam dri-core subfloor with the raised bumps then OSB
6. Just a simple vapour barrier under the underlay and rubber matting. 

7. or any other suggestions. I’m working to a budget, so cheaper options are best. Although I’m doing spray foam on the basement walls and a pony wall, given the age of the rest of the house, I’m also questioning the value of cost spend on extra basement floor insulation. I’ll be installing myself. 

Thanks. 

Paul