HELP!!! I built a new deck two summers ago. We used 3/4 x5 1/2 cumaru. I reused a portion of my old deck joists. Deck moves 21 feet away from house. Ground underneath goes from a foot to 5 feet. I am experiencing lots of cupping and screw coming loose. I have re-tightened the whole deck last year but it looks like i need to again. I don't know if the loose screws are allowing the cupping or the cupping is loosening the screws. either way i need to fix it. I used a #7 drill bit with #8 trimhead screws when we built it. Should i pull up the boards and put down adhesive the screw it with#9 screws. I also considered flipping the cupped ones over and screwing the center as well as the edges