Dogs pooping on deck?

I've read that once the scent of poop is there ,they like going back to the same place even if you've cleaned it up. You need to use a really strong cleaning product to remove every trace of scent. Although it sounds gross, smear a bit of poop where you DO want them to poop. It may take a while if they are not under constant supervision-pay a local student/kid to doggy sit for a few days if you are working long hours? Maybe try feeding them on the deck- they shouldn't like pooping near where they eat. Good luck.