If you just built the deck 2 things will happen in what you posted.
One is that the deck boards themselves will shrink and those (I hate them also) little pesky seeds may start to go through.
TWO..If you use aluminum with the new decking you will find your roof will not last a long time, new PT lumber and aluminum do not mix well due to copper in the PT wood . Even the vynil covered type. Wherever you puncture the coating it may decay and get under the coating. Try something else like Lexan or Ondura for under your deck.
Anyone else ?