Pressure washing deck question.

[shelteredV]

That needs to be sanded, but it looks like there was something applied to the deck already (some kind of sealer) which will just kill sandpaper quick. Even if you put a drum sander on it with someone that knows how to run it, it'll kill belts quick. You should let the deck weather a while, then go at it. It's a shame the guy that washed it didn't know the proper way to use the machine.