I had the stinkiest and slimiest litter the one time I used DE in my litter. Never again! The DE killed off all the healthy organisms that create a composting action. If you have a bad smell then you're not getting a composting action happening.
i began my deep litter with 3-4 inches of well-rotted material from a 2 yr old compost pile to bring in those healthy organisms. Then, when I clean out the coop I always leave a couple inches to keep those organisms in my coop bedding and I'm sure to turn the bedding every few weeks.
Yes, you can certainly do it on concrete--that'd be better than wood which would certainly rot. (My coop is on dirt/gravel, which is great for drainage of any excess moisture.)