Hi Mystyler,
Deck is alloy, done a bit of work on sandy soil, just worn through. Next depends on what you plan for it. If you want to restore it what you can do is clean the inside around the holes, file around the edges of the hole so you are back to clean ally, tape over the hole on the outside and fill the hole on the inside with JB Weld and feather it around the inside edges . How you finish it on the inside depends on whether you want to paint it and make it a showpiece. At least if you use JB Weld moisture won't affect it if you decided you wanted to use it. A quicker cheaper way is to just use body filler but I wouldn't try using it after this method
