New coop being built...should we dust anything before we use it

I wouldn't put anything out until it's needed.
Once DE gets wet, it's useless, and the dust is harmful to breath

 

When our coop was ready for the girls I dusted the floor with DE,then put in a layer of shavings.Now I simply lightly dust the roosts once a week or so and lightly(very very lightly) dust the bedding when fresh shavings are added. We still have plenty of flies(fly strips help wonders) but I've never seen any fly larvae or the like in the bedding(deep litter method not changed in over two months now) and we have very little odor from the coop. I also walk around the run dusting the wet poop piles a couple of times a week to keep down the fly/larvae mess. With the coop only a few feet from the house this method seems to work well in the 90* plus Kentucky summer heat.

Larry