We did a Home Depot radon test and it came up as an avg of 5. I was
wondering if using dry-loc on the concrete block walls might have enough
effect to lower it down a point or so? They currently are unfinished
blocks. I was also thinking if I stuffed some insulation or paper in to the
top of the block sill and then did a spray foam sealer, wouldn't that cut
down on possible infiltration?

Any thoughts?