I have a concrete roof that I don't really want to drill a bunch of holes in to mount solar. Does anyone have any experience with stick on panels? any issue with them staying tight? The old Unisolar panels were thin film so they use more space/watt. I saw another company Lumeta makes them using mono cells. Any info would be helpful. Thanks

You don't need to drill very far into concrete to set an anchor in epoxy.

Can you set the mounts with 1/4" Tapcon screws (blue screws)? If so, those are quick and easy to set with a rotary hammer drill (i.e. Bosch Bulldog or equivalent) and impact driver (i.e. Milwaukee 2657-20 or equivalent) and only require a 3/16" dia. x 1-1/2" deep hole.

Yes, it can be done with tapcons- did it on our other house. I ran across Lumeta panels online and liked the idea of just sticking them on. One issue I have with rack mount panels here is squirrels like to build nests between the panels and roof- then chew on both. Have blown the ground fuse twice on my father in laws house due to them, and almost had the same problem on my sisters house. Every winter we have to eliminate the ones that get it stuck in their head that under the panels is the perfect place for a nest. It will also be worse for us as we go 2000 miles south for at least three months, I can only image what a family of them would do in that amount of time.