| I have a deck and I've pressure washed it so many times that you can't walk
| on it without getting splinters in your feet. Can I treat it with something
| or do I have to sand it down and then treat it? And what is the best
Your best bet is to lightly sand the deck with 80 grit to remove the tufts raised by the pressure washer and, in the future, use the "fan" setting on the nozzle instead of the high pressure setting. The "fan" setting will give the same results without as much wood raising.
Before you treat the deck, you might want to read what they have to say at
Wood as an engineering material. General Technical Report 113.
Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 463 p.
There is a section which deals with "Biodeterioration of Wood" and another on "Finishing of Wood" which will be of some interest to you. It certainly opened my eyes.