OSB over crawl space, need for Vapor-Barrer?

A first time laminate DIYer. Pruchase KronoSwiss silent-clic flooring and am installing it on an OSB subfloor which is over a large crawl space.

I thought that installing over a wood subfloor I would not need a vapor-barrier? Any other indicators that I might need a vapor barrier in addition to the foam?

The carpet I pulled just had a cheap pad on the subfloor with dog-pee dark spots but no obvious water damage.

Also, for one foot long section over a joist, my subfloor has a bit of a bulge to it like: /\

I'm thinking on trying to sand down the top of this ridge to level out the floor. Any other ideas? What is the side effect of a non-level portion of subfloor on laminate?

Thanks. bp

 

i dont see any reason for the moisture barrier........as far as the "bulge" in your floor you need to get it out you need a level floor for you laminate .....what will happen if it is not is first of all it will be noticable by looking at the flooring and second and worse of all it may cause the toungues and grooves to break and ruin your floor