@ProWindowCleaning I’m green to PW as well, but maybe you just needed more dwell time? I looked up products and the one specially made for composit decks wash was just sh and wetting agents. Maybe a combination of Elemonator and GG4? Im interested to see what someone else has to say. I am curious though how sh could affect was appears to be mineral deposits?
I get not wanting to post on pwr. They can be brutal! But just like here lots of knowledge.
Also, now that I’m pressure washing I don’t know why in the world I didn’t start sooner!
Totally get where you’re coming from. Gotta know when to call it a day.
But for the sake of posterity, I’ve taken some time to answer your question:
That would be 2nd gen, then. The older style of composite decks (15+ years ago) was semi-porous and the maker of Trex got their pants sued off for selling it as a maintenance free, stain resistant decking material, when it was in fact quite the opposite. It can be a real nightmare to try and work with.
The new stuff is a fully encapsulated PVC product. Much nicer to clean and maintain.
The Sodium Hydroxide probably wouldn’t hurt it at all, and at this point, if the painters wanted to give it a shot with some hydroxide based paint stripper, they have nothing really to lose.