I'm going to finish my basement. It's 90% below grade. Block foundation. No signs of water with good grade outside and mainly sandy soil. I do however have to run a dehumidifier in the summer or it gets a little musty smelling. No signs of mold on anything down there though. House is in MN.

Questions:

1: Should I use Drylock? Is it worth doing just for giggles since I can never do after I put up the walls? Would this hurt anything if it's not needed? Would this help with not needing a dehumidifier in the summer?

2: Regarding the little gap where the slab meets the block along the perimeter of the basement... Can i just us caulk to fill this? Or should I use something like the drylock cement filler. If so, do I need to worry about expansion in the summer? I want to seal it to prevent Radon gas.

Thanks!!!!